OPENMolcas

OpenMolcas is a quantum chemistry software package developed by scientists and intended to be used by scientists. It includes programs to apply many different electronic structure methods to chemical systems, but its key feature is the multiconfigurational approach, with methods like CASSCF and CASPT2.

Installed versions

25.10 (complied as serial, pymolcas version py2.29)

Submitting an OpenMolcas calculation

The subMOLCAS script submits the <Input file> as a OpenMOLCAS job to the Komondor CPU queue. The corresponding SLURM job submission can be done in the following way:

/opt/software/packages/sharc/subMOLCAS2510 <Input file>

Alternatively, use the following alias:

alias MOLCAS2510='/opt/software/packages/sharc/subMOLCAS2510'

In this case, the job submission can be performed more conveniently with the following command in the input location from the headnode:

MOLCAS2510 <Input file>

Alternatively, alias line can be inserted into your .bash_profile.

Input sample

An example N2.in input:

  &SEWARD
coord
2
Angstrom
N 0.00 0.00 -0.55
N 0.00 0.00   0.55
basis=cc-pvdz
NODEleted
grid input
grid=ultrafine
end of grid input
End of input

&SCF

&RASSCF
LINEAR
NACT = 10 0 0
INACTIVE = 2 0 0 0 2 0 0 0
RAS2 = 1 1 1 0 1 1 1 0

>>foreach DFT in (T:PBE, FT:PBE)
&MCPDFT &END
FUNC=$DFT
End of input
>>enddo

You can find OpenMOLCAS-specific information at the following locations:

https://molcas.gitlab.io/OpenMolcas/sphinx/users.guide/env-overview.html

OpenMolcas should be cited as

OpenMolcas is not a fork or reimplementation of Molcas, it is a large part of the Molcas codebase that has been released as free and open-source software (FOSS) under the Lesser General Public License (LGPL). Some parts of Molcas remain under a different license by decision of their authors (or impossibility to reach them), and are therefore not included in OpenMolcas.

“OpenMolcas: From Source Code to Insight.” J. Chem. Theory Comput. 15 (2019) 5925-5964. https://pubs.acs.org/doi/10.1021/acs.jctc.9b00532

“Modern quantum chemistry with [Open]Molcas.” J. Chem. Phys. 152 (2020) 214117. https://pubs.aip.org/aip/jcp/article/152/21/214117/198678/Modern-quantum-chemistry-with-Open-Molcas

“The OpenMolcas Web: A Community-Driven Approach to Advancing Computational Chemistry.” J. Chem. Theory Comput. 19 (2023) 6933-6991. https://pubs.acs.org/doi/10.1021/acs.jctc.3c00182

Last update by Milán SZŐRI: 2025-11-29