MOLCAS

MOLCAS is a quantum chemistry software developed by scientists to be used by scientists. MOLCAS is a research product and it is used as a platform by the Lund quantum chemistry group in their work to develop new and improved computational tools in quantum chemistry. Most of the codes in the software have newly developed features and the user should not be surprised if a bug is found now and then.The basic philosophy behind MOLCAS is to develop methods that will allow an accurate ab initio treatment of very general electronic structure problems for molecular systems in both ground and excited states.The key feature of MOLCAS is the multiconfigurational approach. MOLCAS contains codes for general and effective multiconfigurational SCF calculations at the Complete Active Space (CASSCF) level, but also employing more restricted MCSCF wave functions (RASSCF). It is also possible, at this level of theory, to optimize geometries for equilibrium and transition states using gradient techniques and to compute force fields and vibrational energies.SCF/DFT, RASSCF, CASPT2, CC methodsSolvent models, QM/MM interfaceFast, accurate, and robust codeFree support and updatesSource code and tools for developmentAttention: at present only the serial version 6.4 is available on CINECA’s SP5

Version: 8.2 (MARCONI), 8.4 (G100)

Availability: GALILEO100, MARCONI

Target: academic

Official web site: http://www.molcas.org/

Related Commands:

MOLCAS contains a set of ab initio quantum chemical programs. They are essentially separate entities, but they are tied together by a shell that can be executed with the command molcas.
To make a calculation using MOLCAS you have to decide on which programs you need to use, prepare input for these, and construct a command procedure file to run the various programs. This command procedure file is then submitted for batch execution.

  • Setup the environment with the command:
module load molcas
  • Read the documentation and an example of a job script¬†
  • with the command:
module help molcas
  • Commands:

- molcas [input-file]
--> executes a command in the MOLCAS system
- molcas help [prgm] --> gives the list of available keywords for program prgm
- molcas help [prgm] [keyword] --> gives description of a keyword
- molcas help environment --> gives a list of MOLCAS specific environment variables
- molcas help basis [element] --> gives a list of basis sets available for an element

Help and Documentation:

  • You can find documentation on the system, with the command

module help molcas

  • A small online help is available on the system typing the commands:

molcas help [prgm] gives the list of available keywords for program prgm
molcas help [prgm] [keyword] gives description of a keyword
molcas help environment gives a list of MOLCAS specific environment variables
molcas help basis [element] gives a list of basis sets available for an element

  • The manual is on the web (here) at the original home page.

CINECA consultants can be reached through the addr: superc@cineca.it