# Interface to PCMSolver by R. Di Remigio¶

Code author: Roberto Di Remigio, T. Daniel Crawford, Andrew C. Simmonett

Section author: Roberto Di Remigio

Module: Keywords, PSI Variables, PCMSolver

PSI4 contains code to interface to the PCMSolver library developed by R. Di Remigio and L. Frediani. The PCMSolver library requires no additional licence, downloads, or configuration. The library allows for calculations in solution with the polarizable continuum model (PCM), a continuum solvation model [Tomasi:2005:2999].

## Installation¶

Binary

• PCMSolver is available as a conda package for Linux and macOS (and Windows, through the Ubuntu shell).

• If using the PSI4 binary, PCMSolver has already been installed alongside.

• If using PSI4 built from source, and anaconda or miniconda has already been installed (instructions at Quick Installation), PCMSolver can be obtained through conda install pcmsolver. Then enable it as a feature with ENABLE_CheMPS2, hint its location with CMAKE_PREFIX_PATH, and rebuild PSI4 to detect PCMSolver and activate dependent code.

• To remove a conda installation, conda remove pcmsolver.

Source

• If using PSI4 built from source and you want PCMSolver built from from source also, enable it as a feature with ENABLE_CheMPS2, and let the build system fetch and build it and activate dependent code.

## Using the polarizable continuum model¶

The inclusion of a PCM description of the solvent into your calculation is achieved by setting PCM true in your input file. PSI4 understands the additional option PCM_SCF_TYPE with possible values total (the default) or separate. The latter forces the separate handling of nuclear and electronic electrostatic potentials and polarization charges. It is mainly useful for debugging.

Note

At present PCM can only be used for energy calculations with SCF wavefunctions and CC wavefunctions in the PTE approximation [Cammi:2009:164104]

Warning

The PCMSolver library cannot exploit molecular point group symmetry.

The PCM model and molecular cavity are specified in a pcm section that has to be explicitly typed in by the user. This additional section follows a syntax that is slightly different from that of PSI4 and is fully documented here

A typical input for a Hartree–Fock calculation with PCM would look like the following:

  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 molecule NH3 { symmetry c1 N -0.0000000001 -0.1040380466 0.0000000000 H -0.9015844116 0.4818470201 -1.5615900098 H -0.9015844116 0.4818470201 1.5615900098 H 1.8031688251 0.4818470204 0.0000000000 units bohr no_reorient no_com } set { basis STO-3G scf_type pk pcm true pcm_scf_type total } pcm = { Units = Angstrom Medium { SolverType = IEFPCM Solvent = Water } Cavity { RadiiSet = UFF Type = GePol Scaling = False Area = 0.3 Mode = Implicit } } 

More examples can be found in the directories with PCM tests pcmsolver/pcm-scf, pcmsolver/pcm-dft, and pcmsolver/pcm-dipole.

## Keywords for PCMSolver¶

### PCM¶

PCM boolean for pcmsolver module

### PCM_SCF_TYPE¶

Use total or separate potentials and charges in the PCM-SCF step.

• Type: string
• Possible Values: TOTAL, SEPARATE
• Default: TOTAL

### PCM_CC_TYPE¶

PCM-CCSD algorithm type.

• Type: string
• Possible Values: PTE
• Default: PTE

## How to configure PCMSolver for building Psi4¶

Role and Dependencies

• Role — In PSI4, PCMSolver is a library that provides additional quantum chemical capabilities (solvation modeling).
• Downstream Dependencies — PSI4 ($$\Leftarrow$$ optional) PCMSolver
• Upstream Dependencies — PCMSolver $$\Leftarrow$$ Fortran, ???