Post-processing of output and databases

Molpro produces an output file that is in XML format with appropriate mark-up for all important results. This file, which has a .xml suffix, conforms strictly to a well-defined schema, and the the schema definition file can be found in the main Molpro source or installation tree in the directory lib/schema. The principal elements of marked-up output are

• jobstep The results from one job step.
• molecule A container for data on a single molecule.
• cml:molecule Molecular geometry in the Chemical Markup Language (CML) format.
• property A computed property, for example an energy or dipole moment.
• table The output of Molpro’s TABLE command in XHTML format.
• basisSet A self-contained description of the orbital basis set.
• orbitals A set of orbitals.
• vibrations Harmonic normal vibrational modes.
• variables Molpro’s internal variables.
• platform Information about the computing system on which a job was run.

Not all of these elements are produced by default in the regular job transcript .xml file; some of them can result from using the PUT,XML to make a separate dump file.

molpro-output is understood by several post-processing programs, including Jmol, sjef, iMolpro, and gmolpro. There is extensive support for it in the pymolpro library, which should be the normal route for accessing data. Pymolpro is available on conda forge, and some examples of its use can be found here.

Pymolpro also provides a facility to store and interrogate sets of molecules, together with information about how they are to be combined in balanced chemical equations. This collection of information is referred to as a database, and can be generated completely manually, or partially by running appropriate Molpro calculations; the library contains also a number of the standard quantum chemistry benchmark sets. Analysis of the database can give a summary of the energy changes associated with each described reaction, and two or more similar databases can be compared reaction by reaction, to give a statistical analysis of the differences between them. See pymolpro documentation for details and examples.