{"id":2193,"date":"2016-07-28T17:57:46","date_gmt":"2016-07-28T21:57:46","guid":{"rendered":"http:\/\/dev.gaussian.com\/?page_id=2193"},"modified":"2024-10-03T11:34:20","modified_gmt":"2024-10-03T15:34:20","slug":"external","status":"publish","type":"page","link":"https:\/\/gaussian.com\/external\/","title":{"rendered":"External"},"content":{"rendered":"<div id=\"g16man\">\n<div class=\"desktop-display\"><div id=\"wonderplugintabs-container-90\" style=\"max-width:100%;margin:0 auto;\"><div style=\"display:none;\" class=\"wonderplugintabs\" id=\"wonderplugintabs-90\" data-tabsid=\"90\" data-width=\"800\" data-height=\"400\" data-skin=\"horizontaltoptabs\" data-enabletabindex=\"false\" data-keyaccess=\"false\" data-fullwidthtabs=\"false\" data-accordion=\"false\" data-accordionmultiple=\"false\" data-accordioncloseall=\"false\" data-switchonmouseover=\"false\" data-savestatusincookie=\"false\" data-extendedheight=\"false\" data-responsive=\"true\" data-fullwidth=\"true\" data-applydisplaynonetohiddenpanel=\"true\" data-triggerresize=\"true\" data-triggerresizeonload=\"true\" data-disablewpautop=\"false\" data-hidetitleonsmallscreen=\"false\" data-donotinit=\"false\" data-addinitscript=\"false\" data-fullwidthtabsonsmallscreen=\"true\" data-accordiononsmallscreen=\"false\" data-heightmode=\"auto\" data-minheight=\"200\" data-firstid=\"0\" data-direction=\"horizontal\" data-tabposition=\"top\" data-tabiconposition=\"left\" data-horizontaltabalign=\"left\" data-hidetitleonsmallscreenwidth=\"768\" data-transition=\"\" data-responsivemode=\"menu\" data-tabarrowmode=\"slide\" data-horizontalarrowwidthsameasheight=\"pixels\" data-horizontalarrowwidth=\"32\" data-arrowprevicon=\"fa-angle-left\" data-arrownexticon=\"fa-angle-right\" data-dropdownmenutext=\"More\" data-dropdownmenuicon=\"fa-angle-down\" data-triggerresizetimeout=\"10\" data-triggerresizeonloadtimeout=\"0\" data-fullwidthtabsonsmallscreenwidth=\"480\" data-jsfolder=\"https:\/\/gaussian.com\/wp-content\/plugins\/wonderplugin-tabs\/engine\/\" data-skinsfoldername=\"skins\" ><div class=\"wonderplugintabs-header-wrap\"><div class=\"wonderplugintabs-header-inner-wrap\"><ul class=\"wonderplugintabs-header-ul\"><li data-slug=\"\" class=\"wonderplugintabs-header-li wonderplugintabs-header-li-first\"><div class=\"wonderplugintabs-header-caption\" style=\"text-align:left;\"><div class=\"wonderplugintabs-header-title\">Description<\/div><\/div><\/li><li data-slug=\"\" class=\"wonderplugintabs-header-li\"><div class=\"wonderplugintabs-header-caption\" style=\"text-align:left;\"><div class=\"wonderplugintabs-header-title\">Script Invocation<\/div><\/div><\/li><li data-slug=\"\" class=\"wonderplugintabs-header-li\"><div class=\"wonderplugintabs-header-caption\" style=\"text-align:left;\"><div class=\"wonderplugintabs-header-title\">File Formats<\/div><\/div><\/li><li data-slug=\"\" class=\"wonderplugintabs-header-li\"><div class=\"wonderplugintabs-header-caption\" style=\"text-align:left;\"><div class=\"wonderplugintabs-header-title\">Options<\/div><\/div><\/li><li data-slug=\"\" class=\"wonderplugintabs-header-li\"><div class=\"wonderplugintabs-header-caption\" style=\"text-align:left;\"><div class=\"wonderplugintabs-header-title\">Related Info<\/div><\/div><\/li><li data-slug=\"\" class=\"wonderplugintabs-header-li wonderplugintabs-header-li-last\"><div class=\"wonderplugintabs-header-caption\" style=\"text-align:left;\"><div class=\"wonderplugintabs-header-title\">Examples<\/div><\/div><\/li><\/ul><\/div><\/div><div class=\"wonderplugintabs-panel-wrap\" style=\"min-height:200px;\"><div class=\"wonderplugintabs-panel wonderplugintabs-panel-first\" data-contentloaded=1><div class=\"wonderplugintabs-panel-inner\"><\/p>\n<p class=\"tabtitle\">Description<\/p>\n<p class=\"text\">Requests a calculation using an <a id=\"external_programs\" class=\"index\"><\/a>external program. This <a id=\"ONIOM_calculations__external_programs_and\" class=\"index\"><\/a>mechanism was originally primarily intended to facilitate the use of external programs to provide the low-level calculations in <a class=\"kw\" href=\"\/oniom\">ONIOM<\/a> calculations. However, it has been made very general. For example, it can also be used to conduct geometry optimizations using Gaussian&#8217;s optimizer with external programs providing the function values and derivatives.<\/p>\n<p class=\"text\">Gaussian uses a standardized interface to run an external program to produce an energy (and optionally a dipole moment or forces) at each geometry. A text file is produced with the current structure, and a script named <span class=\"fn\">Gau_External<\/span> is run by default (see below for information on specifying an alternate script). This script, which is provided by the user, is expected to:<\/p>\n<ul>\n<li class=\"ns\">Convert the text file\u2014referred to as the \u201cinput file\u201d\u2014into input for another program.<\/li>\n<li class=\"ns\">Run that program.<\/li>\n<li class=\"ns\">Convert the results into a standard text form for recovery by Gaussian. The converted file for use by Gaussian is referred to as the \u201coutput file.\u201d<\/li>\n<\/ul>\n<p class=\"text\">You may specify a different script by including its name as the option to the <span class=\"kwit\">External<\/span> keyword: e.g., <span class=\"kwit\">External=MyScript<\/span>.<\/p>\n<p><\/div><\/div><div class=\"wonderplugintabs-panel\" data-contentloaded=1><div class=\"wonderplugintabs-panel-inner\"><\/p>\n<p class=\"tabtitle\">Script Invocation<\/p>\n<p class=\"text\">By default, the <span class=\"fn\">Gau_External<\/span> script is passed six parameters:<\/p>\n<pre>$ <span class=\"bo\">Gau_External<\/span> <span class=\"ital\">layer<\/span> <span class=\"ital\">InputFile<\/span> <span class=\"ital\">OutputFile<\/span> <span class=\"ital\">MsgFile<\/span> <span class=\"ital\">FChkFile<\/span> <span class=\"ital\">MatElFile<\/span>\r\n<\/pre>\n<p class=\"text\">The parameters are defined as follows:<\/p>\n<table class=\"term\">\n<tbody>\n<tr>\n<td class=\"term\"><span class=\"ital\">layer<\/span><\/td>\n<td><\/td>\n<td>A key letter indicating whether the computation is being performed on the real system (<span class=\"kwit\">R<\/span>), the model system of a 2-layer ONIOM or the middle layer of a 3-layer ONIOM (<span class=\"kwit\">M<\/span>), or the model system of a 3-layer ONIOM (<span class=\"kwit\">S<\/span>).<\/td>\n<\/tr>\n<tr>\n<td class=\"term\"><span class=\"ital\">InputFile<\/span><\/td>\n<td><\/td>\n<td>The name of the file Gaussian has prepared as input for the external program.<\/td>\n<\/tr>\n<tr>\n<td class=\"term\"><span class=\"ital\">OutputFile<\/span><\/td>\n<td><\/td>\n<td>The name of the file which should be read in after the external program completes.<\/td>\n<\/tr>\n<tr>\n<td class=\"term\"><span class=\"ital\">MsgFile<\/span><\/td>\n<td><\/td>\n<td>The name of a file for messages; if the script creates this file, then its contents are copied to the Gaussian output file.<\/td>\n<\/tr>\n<tr>\n<td class=\"term\"><span class=\"ital\">FChkFile<\/span><\/td>\n<td><\/td>\n<td>A formatted checkpoint file. If the appropriate options are set to link 402, then this file is created from the read-write file before starting the external script, and may be read to import results after the script finishes instead of Gaussian input being provided via <span class=\"ital\">OutputFile<\/span>. The output formatted checkpoint file can contain an initial two blank lines plus the data to be updated in the usual format; it does not need to contain any information which is to remain unchanged.<\/td>\n<\/tr>\n<tr>\n<td class=\"term\"><span class=\"ital\">MatElFile<\/span><\/td>\n<td><\/td>\n<td>Matrix element file. This is a Fortran unformatted file designed to export data such as the overlap and Core Hamiltonian matrix and two-electron integrals in an extensible format. The structure is documented in <a href=\"\/interfacing\"><span class=\"ital\">GauOpen: Interfacing to Gaussian 16<\/span><\/a>.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"text\">All of these files are deleted by Gaussian once the results have been recovered.<\/p>\n<p class=\"text\">Additional arguments to the script may also be included:<\/p>\n<p class=\"text\"><span class=\"kwit\">External=&#8221;RunTink Amber&#8221;<\/span><\/p>\n<p class=\"text\">In this example, the actual command would be:<\/p>\n<pre>$ <span class=\"bo\">RunTink Amber<\/span> <span class=\"ital\">layer<\/span> <span class=\"ital\">InputFile<\/span> <span class=\"ital\">OutputFile<\/span> <span class=\"ital\">MsgFile<\/span> <span class=\"ital\">FChkFile<\/span> <span class=\"ital\">MatElFile<\/span>\r\n<\/pre>\n<p class=\"text\">The specified script is always passed the parameters mentioned above as its final six arguments.<\/p>\n<p><\/div><\/div><div class=\"wonderplugintabs-panel\" data-contentloaded=1><div class=\"wonderplugintabs-panel-inner\"><\/p>\n<p class=\"tabtitle\">File Formats<\/p>\n<h3 class=\"ksection\">Input File Format<\/h3>\n<p class=\"text\">The input file has the following format:<\/p>\n<table class=\"output\">\n<tbody>\n<tr>\n<td class=\"outpw\"><span class=\"ital\">#atoms\u00a0\u00a0derivatives-requested\u00a0\u00a0charge\u00a0\u00a0spin<\/span><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td class=\"outpw\"><span class=\"ital\">atomic#\u00a0\u00a0x\u00a0\u00a0y\u00a0\u00a0z\u00a0\u00a0MM-charge<\/span><\/td>\n<td class=\"codecomm\">Repeated for each atom.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"text\">The first line specifies the number of atoms in the molecule, what derivatives are to be computed (<span class=\"kwit\">0<\/span>=energy only, <span class=\"kwit\">1<\/span>=first derivatives, <span class=\"kwit\">2<\/span>=second derivatives), and the molecule&#8217;s charge and spin multiplicity (format 4I10). The remaining lines specify the atomic number, coordinates, and molecular mechanics charge for each atom (format I10, 4F20.12).<\/p>\n<h3 class=\"ksection\">Output File Format<\/h3>\n<p class=\"text\">The output file is in fixed format and has the following data (all in atomic units):<\/p>\n<table border=\"0\">\n<tbody>\n<tr valign=\"top\">\n<td align=\"left\"><span class=\"bo\"><span class=\"bo\">Items<\/span><\/span><\/td>\n<td><\/td>\n<td align=\"left\"><span class=\"bo\"><span class=\"bo\">Pseudo Code<\/span><\/span><\/td>\n<td><\/td>\n<td align=\"left\"><span class=\"bo\"><span class=\"bo\">Line Format<\/span><br \/>\n<\/span><\/td>\n<\/tr>\n<tr valign=\"top\">\n<td align=\"left\"><span class=\"ital\">energy, dipole-moment (xyz)<\/span><\/td>\n<td><\/td>\n<td align=\"left\">E, Dip(I), I=1,3<\/td>\n<td><\/td>\n<td align=\"left\">4D20.12<\/td>\n<\/tr>\n<tr valign=\"top\">\n<td align=\"left\"><span class=\"ital\">gradient on atom (xyz)<\/span><\/td>\n<td><\/td>\n<td align=\"left\">FX(J,I), J=1,3; I=1,NAtoms<\/td>\n<td><\/td>\n<td align=\"left\">3D20.12<\/td>\n<\/tr>\n<tr valign=\"top\">\n<td align=\"left\"><span class=\"ital\">polarizability<\/span><\/td>\n<td><\/td>\n<td align=\"left\">Polar(I), I=1,6<\/td>\n<td><\/td>\n<td align=\"left\">3D20.12<\/td>\n<\/tr>\n<tr valign=\"top\">\n<td align=\"left\"><span class=\"ital\">dipole derivatives<\/span><\/td>\n<td><\/td>\n<td align=\"left\">DDip(I), I=1,9*NAtoms<\/td>\n<td><\/td>\n<td align=\"left\">3D20.12<\/td>\n<\/tr>\n<tr valign=\"top\">\n<td align=\"left\"><span class=\"ital\">force constants<\/span><\/td>\n<td><\/td>\n<td align=\"left\">FFX(I), I=1,(3*NAtoms*(3*NAtoms+1))\/2<\/td>\n<td><\/td>\n<td align=\"left\">3D20.12<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"text\">The second section is present only if first derivatives or frequencies were requested, and the final section is present only if frequencies were requested. In the latter case, the Hessian is given in lower triangular form: \u03b1<sub><span class=\"ital\">ij<\/span><\/sub>, <span class=\"ital\">i<\/span>=1 to <span class=\"ital\">N<\/span>, <span class=\"ital\">j<\/span>=1 to <span class=\"ital\">i<\/span>. The dipole moment, polarizability, and dipole derivatives can be zero if none are available.<\/p>\n<p><\/div><\/div><div class=\"wonderplugintabs-panel\" data-contentloaded=1><div class=\"wonderplugintabs-panel-inner\"><\/p>\n<p class=\"tabtitle\">Options<\/p>\n<p class=\"text\">It is possible to provide one-electron or one- and two-electron integrals and other matrix elements to an external program and to recover results such as MOs or densities from the other program. Full details and examples are in the <span class=\"fn\">g16\/doc<\/span> subdirectory (<span class=\"fn\">doc<\/span> folder on Windows). Options must follow the name of the script. Test job 769 serves as an example of some of these options. Note that the formats of some files are controlled by options to the <span class=\"kwit\">Output<\/span> keyword. See also <a href=\"\/interfacing\"><span class=\"ital\">GauOpen: Interfacing to Gaussian 16<\/span><\/a>.<\/p>\n<h4 class=\"option\"><a id=\"External_keyword__InUnf_option\" class=\"index\"><\/a>InUnf<\/h4>\n<p class=\"text\">A unformatted matrix element file will be provided to the external program containing coordinates and one-electron matrix elements (overlap, core Hamiltonian, etc.). Refer to <span class=\"fn\">g16\/doc\/unfdat.txt<\/span> for details on the contents of the file and to <span class=\"fn\">g16\/doc\/rdmat.F<\/span> for a sample program which reads the file and prints its contents. <a id=\"External_keyword__1Elintegrals_option\" class=\"index\"><\/a><span class=\"kwit\">1Elintegrals<\/span> is a synonym for this option.<\/p>\n<h4 class=\"option\"><a id=\"External_keyword__2ElIntegrals_option\" class=\"index\"><\/a>2ElIntegrals<\/h4>\n<p class=\"text\">The unformatted matrix element file should also contain two-electron integrals. This option implies <a class=\"kw\" href=\"\/scf\/?tabid=1#SCF_keyword__Conventional_option\">SCF=Conventional<\/a>.<\/p>\n<h4 class=\"option\"><a id=\"External_keyword__Raw_option\" class=\"index\"><\/a>Raw<\/h4>\n<p class=\"text\">Read or write a raw binary matrix element file rather than an unformatted file.<\/p>\n<h4 class=\"option\"><a id=\"External_keyword__InputFchk_option\" class=\"index\"><\/a>InputFchk<\/h4>\n<p class=\"text\">A formatted checkpoint file should be generated and provided to the external program. <span class=\"kwit\">InFChk<\/span> is a synonym for this option.<\/p>\n<h4 class=\"option\"><a id=\"External_keyword__OutputUnf_option\" class=\"index\"><\/a>OutputUnf<\/h4>\n<p class=\"text\">A unformatted file will be provided to the external program and an updated or replaced file with the same structure will be read by G16 for the results, in lieu of the default text output file expected from the external program\/script. <span class=\"kwit\">OutUnf<\/span> is a synonym for this option.<\/p>\n<h4 class=\"option\"><a id=\"External_keyword__IOFchk_option\" class=\"index\"><\/a>IOFchk<\/h4>\n<p class=\"text\">A formatted checkpoint file will be generated and provided to the external program, and a new <span class=\"fn\">.fchk<\/span> file will be read to import results afterwards. <span class=\"kwit\">OutputFChk<\/span> is a synonym for this option.<\/p>\n<h4 class=\"option\"><a id=\"External_keyword__ReadInputSection_option\" class=\"index\"><\/a>ReadInputSection<\/h4>\n<p class=\"text\">This option can be used to alter the content of the external text input file that Gaussian 16 automatically generates for the external script. When the data transfer between Gaussian 16 and the external script is handled using one of the options above (e.g. <span class=\"kwit\">IOFchk<\/span>), the default external text input file is not needed. With this option, a section (delimited by the usual blank lines) will be read from the Gaussian 16 input file. The text in this section will be placed in the external text input file instead of the usual content of such file. This provides additional flexibility to provide extra instructions to the external script.<\/p>\n<h4 class=\"option\"><a id=\"External_keyword__PostSCF_option\" class=\"index\"><\/a>PostSCF<\/h4>\n<p class=\"text\">Run the external program after the SCF calculation in Gaussian but before the population analysis and molecular property links.<\/p>\n<h4 class=\"option\"><a id=\"External_keyword__PostPop_option\" class=\"index\"><\/a>PostPop<\/h4>\n<p class=\"text\">Run the external program after the SCF calculation and the population analysis and molecular property links.<\/p>\n<h4 class=\"option\"><a id=\"External_keyword__MO2ElIntegrals_option\" class=\"index\"><\/a>MO2ElIntegrals<\/h4>\n<p class=\"text\">Request MO integral transformation and storage in the unf file. Implies <span class=\"kwit\">PostSCF<\/span>.<\/p>\n<h4 class=\"option\"><a id=\"External_keyword__ActiveAtoms_option\" class=\"index\"><\/a>ActiveAtoms<\/h4>\n<h4 class=\"option\"><a id=\"External_keyword__AllAtoms_option\" class=\"index\"><\/a>AllAtoms<\/h4>\n<p class=\"text\">Specifies which atoms are included in the text input and matrix element files for ONIOM calculations. The default is <span class=\"kwit\">AllAtoms<\/span>. <span class=\"kwit\">ActiveAtoms<\/span> includes only the atoms in the model system (high layer).<\/p>\n<h4 class=\"option\"><a id=\"External_keyword__NoDelete_option\" class=\"index\"><\/a>NoDelete<\/h4>\n<p class=\"text\">Retain the intermediate files used.<\/p>\n<h4 class=\"option\"><a id=\"External_keyword__Guess_option\" class=\"index\"><\/a>Guess<\/h4>\n<p class=\"text\">Force Gaussian to generating\/reading an initial guess for orbitals. <span class=\"kwit\">NoGuess<\/span> prevents Gaussian from doing so. The default is <span class=\"kwit\">NoGuess<\/span> unless initial guess options are set, so <span class=\"kwit\">NoGuess<\/span> is useful during ONIOM calculations with <span class=\"kwit\">Guess=Input<\/span> or <span class=\"kwit\">Guess=Read<\/span> for the other models.<\/p>\n<h4 class=\"option\"><a id=\"External_keyword__AO2ElDerivatives_option\" class=\"index\"><\/a>AO2ElDerivatives<\/h4>\n<p class=\"text\">Generate the AO 1-electron and 2-electron integral derivatives and include them in the matrix element file.<\/p>\n<h4 class=\"option\"><a id=\"External_keyword__AO2PDM_option\" class=\"index\"><\/a>AO2PDM<\/h4>\n<p class=\"text\">Save the post-SCF contribution to the 2-particle density matrix on the matrix element file.<\/p>\n<h4 class=\"option\"><a id=\"External_keyword__Files_option\" class=\"index\"><\/a>Files<\/h4>\n<p class=\"text\">Include the contents of the specified internal Gaussian file within the generated matrix element file. For example, the following option:<\/p>\n<pre>External=Files=(123,(456,offset=1,integer=27))<\/pre>\n<p>will cause the contents of internal file 123 (assumed by default to be real values) to be included in the matrix element file (labeled as \u201cFile 123\u201d). The second item in the file list specifies the 27 integers in internal file 456 starting after the first (8-byte) word (labeled as \u201cFile 456 integers section 001\u201d), as well as any real values following the integers (labeled \u201cFile 456 reals section 002\u201d).<\/p>\n<p><\/div><\/div><div class=\"wonderplugintabs-panel\" data-contentloaded=1><div class=\"wonderplugintabs-panel-inner\"><\/p>\n<p class=\"tabtitle\">Related Keywords<\/p>\n<p class=\"text\">External scripts may also be specified as one of the models for the <a class=\"kw\" href=\"\/oniom\">ONIOM<\/a> keyword (see the examples).<\/p>\n<p class=\"text\">The Gaussian stand-alone <a class=\"bo\" href=\"\/mm_util\">mm<\/a> utility program can be run with the <span class=\"bo\">-external<\/span> switch, which causes it to read and write data in the formats used by the External interface.<\/p>\n<p class=\"text\">See <a href=\"\/interfacing\"><span class=\"ital\">GauOpen: Interfacing to Gaussian 16<\/span><\/a> for information about exchanging data with other programs.<\/p>\n<p><\/div><\/div><div class=\"wonderplugintabs-panel wonderplugintabs-panel-last\" data-contentloaded=1><div class=\"wonderplugintabs-panel-inner\"><\/p>\n<p class=\"tabtitle\">Examples<\/p>\n<p class=\"text\">The following route section specifies an external script for the low layer of a 3 layer ONIOM calculation:<\/p>\n<pre># ONIOM(B3LYP\/6-31G(d):AM1:External=\"RunTink Amber\") Opt=NoMicro<\/pre>\n<p class=\"text\">The following route section specifies an external script for the high accuracy layer of a 2 layer ONIOM job:<\/p>\n<pre># ONIOM(External=\"RunCC SDT\":B3LYP\/6-31G(d)) Opt=NoMicro<\/pre>\n<p><\/div><\/div><\/div><\/div><\/div><script>function wondertabs_90_appendcss(csscode) {var head=document.head || document.getElementsByTagName(\"head\")[0];var style=document.createElement(\"style\");head.appendChild(style);style.type=\"text\/css\";if (style.styleSheet){style.styleSheet.cssText=csscode;} else {style.appendChild(document.createTextNode(csscode));}};wondertabs_90_appendcss(\"#wonderplugintabs-90 > .wonderplugintabs-header-wrap { \tbox-sizing: border-box; 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}\");<\/script>\n<\/p><\/div>\n<div class=\"mobile-display\"><div id=\"wonderplugintabs-container-168\" style=\"max-width:800px;margin:0 auto;\"><div style=\"display:none;\" class=\"wonderplugintabs\" id=\"wonderplugintabs-168\" data-tabsid=\"168\" data-width=\"800\" data-height=\"400\" data-skin=\"verticallefttabs\" data-arrowinsidepanel=\"true\" data-arrowloop=\"true\" data-autoexpandpanelheight=\"true\" data-fixedheaderwidth=\"false\" data-fixedheaderheight=\"false\" data-ajaxloading=\"false\" data-ajaxloadingfirst=\"false\" data-ajaxloadingauto=\"false\" data-closeall=\"false\" data-usetablecellfortitle=\"false\" data-enablega=\"false\" data-enabletabindex=\"false\" data-keyaccess=\"false\" data-fullwidthtabs=\"false\" data-accordion=\"false\" data-accordionmultiple=\"false\" data-accordioncloseall=\"false\" data-switchonmouseover=\"false\" data-savestatusincookie=\"false\" data-extendedheight=\"false\" data-responsive=\"true\" data-fullwidth=\"false\" data-applydisplaynonetohiddenpanel=\"true\" data-triggerresize=\"true\" data-triggerresizeonload=\"true\" data-disablewpautop=\"false\" data-hidetitleonsmallscreen=\"false\" data-donotinit=\"false\" data-removeinlinecss=\"true\" data-addinitscript=\"false\" data-fullwidthtabsonsmallscreen=\"true\" data-accordiononsmallscreen=\"true\" data-paneloverflowvisible=\"false\" data-addpanelarrow=\"false\" data-arrowfontsize=\"20\" data-arrowfontcolor=\"#666\" data-headerwidth=\"180\" data-headerheight=\"80\" data-gatrackingid=\"\" data-ga4account=\"\" data-heightmode=\"auto\" data-minheight=\"300\" data-firstid=\"0\" data-direction=\"vertical\" data-tabposition=\"left\" data-tabiconposition=\"left\" data-horizontaltabalign=\"left\" data-hidetitleonsmallscreenwidth=\"768\" data-transition=\"\" data-arrowstyle=\"none\" data-arrowimage=\"arrows-32-32-2.png\" data-arrowwidth=\"32\" data-arrowheight=\"32\" data-prevarrowcss=\"position:absolute;top:50%;left:0;margin-top:-16px;\" data-nextarrowcss=\"position:absolute;top:50%;right:0;margin-top:-16px;\" data-ajaxloadingautodelay=\"500\" data-navstyle=\"none\" data-navwidth=\"16\" data-navheight=\"16\" data-navspacing=\"8\" data-navimage=\"bullet-16-16-0.png\" data-navcss=\"display:block;position:relative;text-align:center;width:100%;top:100%;margin-top:16px;\" data-minimumheadermargin=\"0\" data-responsivemode=\"menu\" data-tabarrowmode=\"slide\" data-horizontalarrowwidthsameasheight=\"pixels\" data-horizontalarrowwidth=\"32\" data-arrowprevicon=\"fa-angle-up\" data-arrownexticon=\"fa-angle-down\" data-dropdownmenutext=\"More\" data-dropdownmenuicon=\"fa-angle-right\" data-triggerresizetimeout=\"100\" data-triggerresizeonloadtimeout=\"100\" data-fullwidthtabsonsmallscreenwidth=\"480\" data-jsfolder=\"https:\/\/gaussian.com\/wp-content\/plugins\/wonderplugin-tabs\/engine\/\" data-skinsfoldername=\"skins\" ><div class=\"wonderplugintabs-header-wrap\"><div class=\"wonderplugintabs-header-inner-wrap\"><ul class=\"wonderplugintabs-header-ul\"><li data-slug=\"\" class=\"wonderplugintabs-header-li wonderplugintabs-header-li-first\"><div class=\"wonderplugintabs-header-caption\" style=\"text-align:left;\"><div class=\"wonderplugintabs-header-title\">Description<\/div><\/div><\/li><li data-slug=\"\" class=\"wonderplugintabs-header-li\"><div class=\"wonderplugintabs-header-caption\" style=\"text-align:left;\"><div class=\"wonderplugintabs-header-title\">Script Innovation<\/div><\/div><\/li><li data-slug=\"\" class=\"wonderplugintabs-header-li\"><div class=\"wonderplugintabs-header-caption\" style=\"text-align:left;\"><div class=\"wonderplugintabs-header-title\">File Formats<\/div><\/div><\/li><li data-slug=\"\" class=\"wonderplugintabs-header-li\"><div class=\"wonderplugintabs-header-caption\" style=\"text-align:left;\"><div class=\"wonderplugintabs-header-title\">Options<\/div><\/div><\/li><li data-slug=\"\" class=\"wonderplugintabs-header-li\"><div class=\"wonderplugintabs-header-caption\" style=\"text-align:left;\"><div class=\"wonderplugintabs-header-title\">Related Info<\/div><\/div><\/li><li data-slug=\"\" class=\"wonderplugintabs-header-li wonderplugintabs-header-li-last\"><div class=\"wonderplugintabs-header-caption\" style=\"text-align:left;\"><div class=\"wonderplugintabs-header-title\">Examples<\/div><\/div><\/li><\/ul><\/div><\/div><div class=\"wonderplugintabs-panel-wrap\" style=\"min-height:300px;\"><div class=\"wonderplugintabs-panel wonderplugintabs-panel-first\" data-contentloaded=1><div class=\"wonderplugintabs-panel-inner\"><p class=\"text\">Requests a calculation using an <a id=\"external_programs\" class=\"index\"><\/a>external program. This <a id=\"ONIOM_calculations__external_programs_and\" class=\"index\"><\/a>mechanism was originally primarily intended to facilitate the use of external programs to provide the low-level calculations in <a class=\"kw\" href=\"\/oniom\">ONIOM<\/a> calculations. However, it has been made very general. For example, it can also be used to conduct geometry optimizations using Gaussian's optimizer with external programs providing the function values and derivatives.<\/p>\n<p class=\"text\">Gaussian uses a standardized interface to run an external program to produce an energy (and optionally a dipole moment or forces) at each geometry. A text file is produced with the current structure, and a script named <span class=\"fn\">Gau_External<\/span> is run by default (see below for information on specifying an alternate script). This script, which is provided by the user, is expected to:<\/p>\n\n<ul>\n \t<li class=\"ns\">Convert the text file\u2014referred to as the \u201cinput file\u201d\u2014into input for another program.<\/li>\n \t<li class=\"ns\">Run that program.<\/li>\n \t<li class=\"ns\">Convert the results into a standard text form for recovery by Gaussian. The converted file for use by Gaussian is referred to as the \u201coutput file.\u201d<\/li>\n<\/ul>\n<p class=\"text\">You may specify a different script by including its name as the option to the <span class=\"kwit\">External<\/span> keyword: e.g., <span class=\"kwit\">External=MyScript<\/span>.<\/p><\/div><\/div><div class=\"wonderplugintabs-panel\" data-contentloaded=1><div class=\"wonderplugintabs-panel-inner\"><p class=\"text\">By default, the <span class=\"fn\">Gau_External<\/span> script is passed six parameters:<\/p>\n\n<pre>$ <span class=\"bo\">Gau_External<\/span> <span class=\"ital\">layer<\/span> <span class=\"ital\">InputFile<\/span> <span class=\"ital\">OutputFile<\/span> <span class=\"ital\">MsgFile<\/span> <span class=\"ital\">FChkFile<\/span> <span class=\"ital\">MatElFile<\/span>\n<\/pre>\n<p class=\"text\">The parameters are defined as follows:<\/p>\n\n<table class=\"term\">\n<tbody>\n<tr>\n<td class=\"term\"><span class=\"ital\">layer<\/span><\/td>\n<td><\/td>\n<td>A key letter indicating whether the computation is being performed on the real system (<span class=\"kwit\">R<\/span>), the model system of a 2-layer ONIOM or the middle layer of a 3-layer ONIOM (<span class=\"kwit\">M<\/span>), or the model system of a 3-layer ONIOM (<span class=\"kwit\">S<\/span>).<\/td>\n<\/tr>\n<tr>\n<td class=\"term\"><span class=\"ital\">InputFile<\/span><\/td>\n<td><\/td>\n<td>The name of the file Gaussian has prepared as input for the external program.<\/td>\n<\/tr>\n<tr>\n<td class=\"term\"><span class=\"ital\">OutputFile<\/span><\/td>\n<td><\/td>\n<td>The name of the file which should be read in after the external program completes.<\/td>\n<\/tr>\n<tr>\n<td class=\"term\"><span class=\"ital\">MsgFile<\/span><\/td>\n<td><\/td>\n<td>The name of a file for messages; if the script creates this file, then its contents are copied to the Gaussian output file.<\/td>\n<\/tr>\n<tr>\n<td class=\"term\"><span class=\"ital\">FChkFile<\/span><\/td>\n<td><\/td>\n<td>A formatted checkpoint file. If the appropriate options are set to link 402, then this file is created from the read-write file before starting the external script, and may be read to import results after the script finishes instead of Gaussian input being provided via <span class=\"ital\">OutputFile<\/span>. The output formatted checkpoint file can contain an initial two blank lines plus the data to be updated in the usual format; it does not need to contain any information which is to remain unchanged.<\/td>\n<\/tr>\n<tr>\n<td class=\"term\"><span class=\"ital\">MatElFile<\/span><\/td>\n<td><\/td>\n<td>Matrix element file. This is a Fortran unformatted file designed to export data such as the overlap and Core Hamiltonian matrix and two-electron integrals in an extensible format. The structure is documented in <a href=\"\/interfacing\"><span class=\"ital\">GauOpen: Interfacing to Gaussian 16<\/span><\/a>.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"text\">All of these files are deleted by Gaussian once the results have been recovered.<\/p>\n<p class=\"text\">Additional arguments to the script may also be included:<\/p>\n<p class=\"text\"><span class=\"kwit\">External=\"RunTink Amber\"<\/span><\/p>\n<p class=\"text\">In this example, the actual command would be:<\/p>\n\n<pre>$ <span class=\"bo\">RunTink Amber<\/span> <span class=\"ital\">layer<\/span> <span class=\"ital\">InputFile<\/span> <span class=\"ital\">OutputFile<\/span> <span class=\"ital\">MsgFile<\/span> <span class=\"ital\">FChkFile<\/span> <span class=\"ital\">MatElFile<\/span>\n<\/pre>\n<p class=\"text\">The specified script is always passed the parameters mentioned above as its final six arguments.<\/p><\/div><\/div><div class=\"wonderplugintabs-panel\" data-contentloaded=1><div class=\"wonderplugintabs-panel-inner\"><p class=\"text\">The input file has the following format:<\/p>\n\n<table class=\"output\">\n<tbody>\n<tr>\n<td class=\"outpw\"><span class=\"ital\">#atoms\u00a0\u00a0derivatives-requested\u00a0\u00a0charge\u00a0\u00a0spin<\/span><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td class=\"outpw\"><span class=\"ital\">atomic#\u00a0\u00a0x\u00a0\u00a0y\u00a0\u00a0z\u00a0\u00a0MM-charge<\/span><\/td>\n<td class=\"codecomm\">Repeated for each atom.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"text\">The first line specifies the number of atoms in the molecule, what derivatives are to be computed (<span class=\"kwit\">0<\/span>=energy only, <span class=\"kwit\">1<\/span>=first derivatives, <span class=\"kwit\">2<\/span>=second derivatives), and the molecule's charge and spin multiplicity (format 4I10). The remaining lines specify the atomic number, coordinates, and molecular mechanics charge for each atom (format I10, 4F20.12).<\/p>\n\n<h3 class=\"ksection\">Output File Format<\/h3>\n<p class=\"text\">The output file is in fixed format and has the following data (all in atomic units):<\/p>\n\n<table border=\"0\">\n<tbody>\n<tr valign=\"top\">\n<td align=\"left\"><span class=\"bo\"><span class=\"bo\">Items<\/span><\/span><\/td>\n<td><\/td>\n<td align=\"left\"><span class=\"bo\"><span class=\"bo\">Pseudo Code<\/span><\/span><\/td>\n<td><\/td>\n<td align=\"left\"><span class=\"bo\"><span class=\"bo\">Line Format<\/span>\n<\/span><\/td>\n<\/tr>\n<tr valign=\"top\">\n<td align=\"left\"><span class=\"ital\">energy, dipole-moment (xyz)<\/span><\/td>\n<td><\/td>\n<td align=\"left\">E, Dip(I), I=1,3<\/td>\n<td><\/td>\n<td align=\"left\">4D20.12<\/td>\n<\/tr>\n<tr valign=\"top\">\n<td align=\"left\"><span class=\"ital\">gradient on atom (xyz)<\/span><\/td>\n<td><\/td>\n<td align=\"left\">FX(J,I), J=1,3; I=1,NAtoms<\/td>\n<td><\/td>\n<td align=\"left\">3D20.12<\/td>\n<\/tr>\n<tr valign=\"top\">\n<td align=\"left\"><span class=\"ital\">polarizability<\/span><\/td>\n<td><\/td>\n<td align=\"left\">Polar(I), I=1,6<\/td>\n<td><\/td>\n<td align=\"left\">3D20.12<\/td>\n<\/tr>\n<tr valign=\"top\">\n<td align=\"left\"><span class=\"ital\">dipole derivatives<\/span><\/td>\n<td><\/td>\n<td align=\"left\">DDip(I), I=1,9*NAtoms<\/td>\n<td><\/td>\n<td align=\"left\">3D20.12<\/td>\n<\/tr>\n<tr valign=\"top\">\n<td align=\"left\"><span class=\"ital\">force constants<\/span><\/td>\n<td><\/td>\n<td align=\"left\">FFX(I), I=1,(3*NAtoms*(3*NAtoms+1))\/2<\/td>\n<td><\/td>\n<td align=\"left\">3D20.12<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"text\">The second section is present only if first derivatives or frequencies were requested, and the final section is present only if frequencies were requested. In the latter case, the Hessian is given in lower triangular form: \u03b1<sub><span class=\"ital\">ij<\/span><\/sub>, <span class=\"ital\">i<\/span>=1 to <span class=\"ital\">N<\/span>, <span class=\"ital\">j<\/span>=1 to <span class=\"ital\">i<\/span>. The dipole moment, polarizability, and dipole derivatives can be zero if none are available.<\/p><\/div><\/div><div class=\"wonderplugintabs-panel\" data-contentloaded=1><div class=\"wonderplugintabs-panel-inner\"><p class=\"text\">It is possible to provide one-electron or one- and two-electron integrals and other matrix elements to an external program and to recover results such as MOs or densities from the other program. Full details and examples are in the <span class=\"fn\">g16\/doc<\/span> subdirectory (<span class=\"fn\">doc<\/span> folder on Windows). Options must follow the name of the script. Test job 769 serves as an example of some of these options. Note that the formats of some files are controlled by options to the <span class=\"kwit\">Output<\/span> keyword. See also <a href=\"\/interfacing\"><span class=\"ital\">GauOpen: Interfacing to Gaussian 16<\/span><\/a>.<\/p>\n\n<h4 class=\"option\"><a id=\"External_keyword__InUnf_option\" class=\"index\"><\/a>InUnf<\/h4>\n<p class=\"text\">A unformatted matrix element file will be provided to the external program containing coordinates and one-electron matrix elements (overlap, core Hamiltonian, etc.). Refer to <span class=\"fn\">g16\/doc\/unfdat.txt<\/span> for details on the contents of the file and to <span class=\"fn\">g16\/doc\/rdmat.F<\/span> for a sample program which reads the file and prints its contents. <a id=\"External_keyword__1Elintegrals_option\" class=\"index\"><\/a><span class=\"kwit\">1Elintegrals<\/span> is a synonym for this option.<\/p>\n\n<h4 class=\"option\"><a id=\"External_keyword__2ElIntegrals_option\" class=\"index\"><\/a>2ElIntegrals<\/h4>\n<p class=\"text\">The unformatted matrix element file should also contain two-electron integrals. This option implies <a class=\"kw\" href=\"\/scf\/?tabid=1#SCF_keyword__Conventional_option\">SCF=Conventional<\/a>.<\/p>\n\n<h4 class=\"option\"><a id=\"External_keyword__Raw_option\" class=\"index\"><\/a>Raw<\/h4>\n<p class=\"text\">Read or write a raw binary matrix element file rather than an unformatted file.<\/p>\n\n<h4 class=\"option\"><a id=\"External_keyword__InputFchk_option\" class=\"index\"><\/a>InputFchk<\/h4>\n<p class=\"text\">A formatted checkpoint file should be generated and provided to the external program. <span class=\"kwit\">InFChk<\/span> is a synonym for this option.<\/p>\n\n<h4 class=\"option\"><a id=\"External_keyword__OutputUnf_option\" class=\"index\"><\/a>OutputUnf<\/h4>\n<p class=\"text\">A unformatted file will be provided to the external program and an updated or replaced file with the same structure will be read by G16 for the results, in lieu of the default text output file expected from the external program\/script. <span class=\"kwit\">OutUnf<\/span> is a synonym for this option.<\/p>\n\n<h4 class=\"option\"><a id=\"External_keyword__IOFchk_option\" class=\"index\"><\/a>IOFchk<\/h4>\n<p class=\"text\">A formatted checkpoint file will be generated and provided to the external program, and a new <span class=\"fn\">.fchk<\/span> file will be read to import results afterwards. <span class=\"kwit\">OutputFChk<\/span> is a synonym for this option.<\/p>\n\n<h4 class=\"option\"><a id=\"External_keyword__ReadInputSection_option\" class=\"index\"><\/a>ReadInputSection<\/h4>\n<p class=\"text\">This option can be used to alter the content of the external text input file that Gaussian 16 automatically generates for the external script. When the data transfer between Gaussian 16 and the external script is handled using one of the options above (e.g. <span class=\"kwit\">IOFchk<\/span>), the default external text input file is not needed. With this option, a section (delimited by the usual blank lines) will be read from the Gaussian 16 input file. The text in this section will be placed in the external text input file instead of the usual content of such file. This provides additional flexibility to provide extra instructions to the external script.<\/p>\n\n<h4 class=\"option\"><a id=\"External_keyword__PostSCF_option\" class=\"index\"><\/a>PostSCF<\/h4>\n<p class=\"text\">Run the external program after the SCF calculation in Gaussian but before the population analysis and molecular property links.<\/p>\n\n<h4 class=\"option\"><a id=\"External_keyword__PostPop_option\" class=\"index\"><\/a>PostPop<\/h4>\n<p class=\"text\">Run the external program after the SCF calculation and the population analysis and molecular property links.<\/p>\n\n<h4 class=\"option\"><a id=\"External_keyword__MO2ElIntegrals_option\" class=\"index\"><\/a>MO2ElIntegrals<\/h4>\n<p class=\"text\">Request MO integral transformation and storage in the unf file. Implies <span class=\"kwit\">PostSCF<\/span>.<\/p>\n\n<h4 class=\"option\"><a id=\"External_keyword__ActiveAtoms_option\" class=\"index\"><\/a>ActiveAtoms<\/h4>\n<h4 class=\"option\"><a id=\"External_keyword__AllAtoms_option\" class=\"index\"><\/a>AllAtoms<\/h4>\n<p class=\"text\">Specifies which atoms are included in the text input and matrix element files for ONIOM calculations. The default is <span class=\"kwit\">AllAtoms<\/span>. <span class=\"kwit\">ActiveAtoms<\/span> includes only the atoms in the model system (high layer).<\/p>\n\n<h4 class=\"option\"><a id=\"External_keyword__NoDelete_option\" class=\"index\"><\/a>NoDelete<\/h4>\n<p class=\"text\">Retain the intermediate files used.<\/p>\n\n<h4 class=\"option\"><a id=\"External_keyword__Guess_option\" class=\"index\"><\/a>Guess<\/h4>\n<p class=\"text\">Force Gaussian to generating\/reading an initial guess for orbitals. <span class=\"kwit\">NoGuess<\/span> prevents Gaussian from doing so. The default is <span class=\"kwit\">NoGuess<\/span> unless initial guess options are set, so <span class=\"kwit\">NoGuess<\/span> is useful during ONIOM calculations with <span class=\"kwit\">Guess=Input<\/span> or <span class=\"kwit\">Guess=Read<\/span> for the other models.<\/p>\n\n<h4 class=\"option\"><a id=\"External_keyword__AO2ElDerivatives_option\" class=\"index\"><\/a>AO2ElDerivatives<\/h4>\n<p class=\"text\">Generate the AO 1-electron and 2-electron integral derivatives and include them in the matrix element file.<\/p>\n\n<h4 class=\"option\"><a id=\"External_keyword__AO2PDM_option\" class=\"index\"><\/a>AO2PDM<\/h4>\n<p class=\"text\">Save the post-SCF contribution to the 2-particle density matrix on the matrix element file.<\/p>\n\n<h4 class=\"option\"><a id=\"External_keyword__Files_option\" class=\"index\"><\/a>Files<\/h4>\n<p class=\"text\">Include the contents of the specified internal Gaussian file within the generated matrix element file. For example, the following option:<\/p>\n\n<pre>External=Files=(123,(456,offset=1,integer=27))<\/pre>\nwill cause the contents of internal file 123 (assumed by default to be real values) to be included in the matrix element file (labeled as \u201cFile 123\u201d). The second item in the file list specifies the 27 integers in internal file 456 starting after the first (8-byte) word (labeled as \u201cFile 456 integers section 001\u201d), as well as any real values following the integers (labeled \u201cFile 456 reals section 002\u201d).<\/div><\/div><div class=\"wonderplugintabs-panel\" data-contentloaded=1><div class=\"wonderplugintabs-panel-inner\"><p class=\"text\">External scripts may also be specified as one of the models for the <a class=\"kw\" href=\"\/oniom\">ONIOM<\/a> keyword (see the examples).<\/p>\n<p class=\"text\">The Gaussian stand-alone <a class=\"bo\" href=\"\/mm_util\">mm<\/a> utility program can be run with the <span class=\"bo\">-external<\/span> switch, which causes it to read and write data in the formats used by the External interface.<\/p>\n<p class=\"text\">See <a href=\"\/interfacing\"><span class=\"ital\">GauOpen: Interfacing to Gaussian 16<\/span><\/a> for information about exchanging data with other programs.<\/p><\/div><\/div><div class=\"wonderplugintabs-panel wonderplugintabs-panel-last\" data-contentloaded=1><div class=\"wonderplugintabs-panel-inner\"><p class=\"text\">The following route section specifies an external script for the low layer of a 3 layer ONIOM calculation:<\/p>\n\n<pre># ONIOM(B3LYP\/6-31G(d):AM1:External=\"RunTink Amber\") Opt=NoMicro<\/pre>\n<p class=\"text\">The following route section specifies an external script for the high accuracy layer of a 2 layer ONIOM job:<\/p>\n\n<pre># ONIOM(External=\"RunCC SDT\":B3LYP\/6-31G(d)) Opt=NoMicro<\/pre><\/div><\/div><\/div><\/div><\/div><script>function wondertabs_168_appendcss(csscode) {var head=document.head || document.getElementsByTagName(\"head\")[0];var style=document.createElement(\"style\");head.appendChild(style);style.type=\"text\/css\";if (style.styleSheet){style.styleSheet.cssText=csscode;} else {style.appendChild(document.createTextNode(csscode));}};wondertabs_168_appendcss(\"#wonderplugintabs-168 > .wonderplugintabs-header-wrap { \tbox-sizing: border-box; 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}  #wonderplugintabs-168 > .wonderplugintabs-header-wrap .wonderplugintabs-header-li-fullwidth .wonderplugintabs-header-caption:after { \tposition:absolute; \tcolor:#0309b7; \ttop: 12px; \tright:8px; \tcontent: \\\"\\\\f107\\\"; \tfont-family: FontAwesome; \tfont-size: 16px; \tfont-weight:400; }  #wonderplugintabs-168 > .wonderplugintabs-header-wrap .wonderplugintabs-header-li-fullwidth.wonderplugintabs-header-li-active .wonderplugintabs-header-caption:after { \tcontent: \\\"\\\\f106\\\"; }\");<\/script><\/div>\n<style media=\"all\">\n.mobile-display{display:none}\n.desktop-display{display:block}\n@media (max-width:767px){\n.desktop-display {display:none}\n.mobile-display {display:block}\n}\n<\/style>\n<p><script>\ndocument.addEventListener(\"DOMContentLoaded\", function () {\nvar mobileTabs = document.getElementById(\"mobile-tabs\");\nvar desktopTabs = document.getElementById(\"desktop-tabs\");\n<\/script><\/p>\n<p class=\"upd\">Last updated on: 30 August 2022. [G16 Rev. C.01]<\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Last updated on: 30 August 2022. [G16 Rev. C.01]<\/p>\n","protected":false},"author":10,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"page-template-testing.php","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[22,17],"tags":[],"class_list":["post-2193","page","type-page","status-publish","hentry","category-kw","category-ur"],"_links":{"self":[{"href":"https:\/\/gaussian.com\/wp-json\/wp\/v2\/pages\/2193","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gaussian.com\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/gaussian.com\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/gaussian.com\/wp-json\/wp\/v2\/users\/10"}],"replies":[{"embeddable":true,"href":"https:\/\/gaussian.com\/wp-json\/wp\/v2\/comments?post=2193"}],"version-history":[{"count":65,"href":"https:\/\/gaussian.com\/wp-json\/wp\/v2\/pages\/2193\/revisions"}],"predecessor-version":[{"id":18077,"href":"https:\/\/gaussian.com\/wp-json\/wp\/v2\/pages\/2193\/revisions\/18077"}],"wp:attachment":[{"href":"https:\/\/gaussian.com\/wp-json\/wp\/v2\/media?parent=2193"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gaussian.com\/wp-json\/wp\/v2\/categories?post=2193"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gaussian.com\/wp-json\/wp\/v2\/tags?post=2193"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}