Which Quantum Chemistry Output Files Can Chemissian Analyze?

Updated

Chemissian can read output files from Gaussian, US-GAMESS, Firefly/PC-GAMESS, Q-Chem, Molpro, NWChem, ORCA, Turbomole, and Spartan. For UV-VIS spectrum work, the file must contain TDDFT or CIS results; for molecular orbital (MO) energy-level diagrams, the output needs Hartree-Fock or Kohn-Sham data. The program's graphical interface is built to examine and visualize data from these files, so in practice you load the output produced by one of these packages and work with it inside Chemissian rather than converting it first.

Supported Programs and What Each Is Used For

The table below groups the packages by the tasks the site describes. All of them are listed as sources Chemissian can read.

Program Typical use in Chemissian
Gaussian MO diagrams, UV-VIS spectra, density and population analysis
US-GAMESS MO diagrams and electronic structure analysis
Firefly / PC-GAMESS MO diagrams, UV-VIS spectra
Q-Chem MO diagrams, UV-VIS spectra
Molpro Electronic structure data import
NWChem MO diagrams, UV-VIS spectra
ORCA MO diagrams, UV-VIS spectra
Turbomole Electronic structure data import
Spartan MO diagrams, UV-VIS spectra

The site's feature descriptions name GAMESS, Firefly (PC-GAMESS), GAUSSIAN, Spartan, NWChem, Orca, and Q-Chem specifically for spectrum building. Molpro and Turbomole appear in the general list of supported output formats.

What the Output File Must Contain

Support depends on the calculation type, not just the program name:

  • MO energy-level diagrams require Hartree-Fock or Kohn-Sham results, since Chemissian builds diagrams with both methods.
  • UV-VIS spectra require TDDFT or CIS data in the output. A file from a supported program without these results will not produce a spectrum.
  • Comparison with experiment works by plotting calculated and experimental UV-VIS spectra on the same graph, so you need both the calculated output and your experimental spectrum data.

If a file loads but a feature is unavailable, check the calculation type before assuming the format is unsupported.

What You Can Do Once the File Is Loaded

  • MO diagrams: add text labels, connect energy levels with lines, "occupy" levels with electrons, and navigate between levels by keyboard or mouse. Contributions from atomic or molecular fragments can be shown on a contribution diagram or directly on the MO diagram.
  • UV-VIS analysis: build and visualize spectra, study the nature of transitions, and place calculated and experimental spectra on one plot.
  • Density and orbitals: calculate and visualize spin natural orbitals, natural transition orbitals, and electronic and spin densities, prepared for publication.
  • Populations and valences: calculate populations and valences from the imported data.

Practical Notes Before You Start

  • Confirm your program is on the list above. Outputs from packages not named on the site are not described as supported.
  • For spectra, verify the job actually wrote TDDFT or CIS results; this is the most common reason a spectrum cannot be built.
  • The site offers a Download page, an Order page, and Online Help, so you can check availability and licensing there before committing to a workflow. Pricing and access terms are not stated in the material reviewed here, so confirm them on those pages rather than assuming free use.

If your goal is simply to know whether Chemissian fits your existing workflow, the deciding question is whether your calculations come from one of the nine listed packages and include the relevant results (HF/Kohn-Sham for MO diagrams, TDDFT/CIS for spectra).