IEF-PCM for SMD olvation model

Questions
#1

I was performing a single-point calculation using the SMD solvation model with the methanol descriptor (taken from https://comp.chem.umn.edu/solvation/mnsddb.pdf). Below is my input

$molecule
0 1
C 0.000000 0.000000 -0.542500
O 0.000000 0.000000 0.677500
H 0.000000 0.9353074360871938 -1.082500
H 0.000000 -0.9353074360871938 -1.082500
$end

$rem
METHOD hf
BASIS 6-31g
SYM_IGNORE true
SCF_CONVERGENCE 9
SOLVENT_METHOD SMD
$end

$smx
solvent other
epsilon 32.613
SolN 1.3288
SolA 0.43
SolB 0.47
SolG 31.77
SolC 0.000 ! could be omitted
SolH 0.000 ! could be omitted
print 2
$end

I noticed that QChem defaults to using C-PCM for the electrostatic part. Is there a way to change it to IEF-PCM?

Thanks in advance
Arpan

#2

It looks like you can do this in the same way that you would run IEF-PCM normally, i.e., by adding the following to your input file:

$pcm
theory iefpcm
$end

That said, I don’t really recommend IEF-PCM. In polar solvents it’s negligibly different from C-PCM and even in nonpolar solvents (where some people claim that IEF-PCM is better justified, theoretically) I think that the differences are so small that they are within the intrinisic accuracy of the implicit solvation model. See
https://doi.org/10.1002/wcms.1519

1 Like