# Example: COSMO: HCl¶

Download Solv_HCl.run

#! /bin/sh

# Computing solvent effects, with the COSMO model, is illustrated in the HCl
# example.

# After a non-solvent (reference) calculation, which is omitted here, two
# solvent runs are presented, with somewhat different settings for a few input
# parameters. The block key Solvation controls all solvent-related input.

# All subkeys in the SOLVATION block are discussed in the User's Guide. Most of
# them are rather technical and should not severely affect the outcome.
# Physically relevant is the specification of the solute properties, by the
# SOLVENT subkey: the dielectric constant and the effective radius of the
# solvent molecule.

# Note that a non-electrostatic terms as a function of surface area is included
# in the COSMO calculation, by setting the values for CAV0 and CAV1 in the
# subkey SOLVENT of the key SOLVATION. In ADF2010 one should explicitly include
# such values for CAV0 and CAV1, otherwise this non-electrostatic term will be
# taken to be zero, since the defaults have changed in ADF2010.

# A rather strong impact on the computation times has the method of treating the
# 'C-matrix'. There are 3 options (see the User's Guide): EXACT is the most
# expensive, but presumably most accurate. POTENTIAL is the cheapest alternative
# and is usually quite adequate. EXACT uses the exact charge density for the
# Coulomb interaction between the molecular charge distribution and the point
# charges (on the Van der Waals type molecular surface) which model the effects
# of the solvent. The alternatives, notably 'POTENTIAL', use the fitted charge
# density instead. Assuming that the fit is a fairly accurate approximation to
# the exact charge density, the difference in outcome should be marginal.

$ADFBIN/adf <<eor TITLE HCl(0) reference run (gas phase) ATOMS H 0.000000 0.000000 0.000000 Cl 1.304188 0.000000 0.000000 END Basis Type DZP End NOPRINT Bas EigSFO EKin SFO, frag, functions EPRINT SCF NoEigvec END eor rm TAPE21 logfile$ADFBIN/adf <<eor
TITLE  HCl(1) Solv-excl surfac; Gauss-Seidel (old std options)

SYMMETRY  NOSYM

ATOMS
H    0.000000     0.000000    0.000000    R=1.18
Cl   1.304188     0.000000    0.000000    R=1.75
END

Fragments
H  t21.H
Cl t21.Cl
End

SOLVATION
Surf      delley
Div       ND=4  min=0.5  Ofac=0.8
Charged   Method=Gauss-Seidel
Disc      SCale=0.01  LEGendre=10 TOLerance=1.0e-2
SCF       Variational
C-Mat       Exact
END

NOPRINT Bas EigSFO EKin SFO, frag, functions
EPRINT
SCF NoEigvec
END
eor

rm TAPE21 logfile

# In the second solvent run, another (technical) method is used for determining
# the charge distribution on the cavity surface (conjugate-gradient versus
# Gauss-Seidel in the previous calculation), and the POTENTIAL variety is used
# for the C-matrix handling. The results show that it makes little difference in
# outcome, but quite a bit in computation times.

TITLE  HCl(9) NoDisk and Cmatrix potential

FRAGMENTS
H    t21.H
Cl   t21.Cl
END

ATOMS
H    0.000000     0.000000    0.000000    R=1.18
Cl   1.304188     0.000000    0.000000    R=1.75
END

SOLVATION