# Solvation calculation in Gaussian 94

*From*: Shiang-Tai Lin <stlin "at@at" UDel.Edu>
*Subject*: Solvation calculation in Gaussian 94
*Date*: Thu, 13 Aug 1998 22:01:25 -0400 (EDT)

Dear CCL users,
I was trying to use G94 to do some solvation calculations and
had difficulty in understanding the meanings of some of the
output lines. I appreciate any of your help.
In the input file, I wrote
#T rhf/6-31g(d) scrf=ipcm volume test
The output due to the keyword "volume" are
Box volume = 2398.137 fraction occupied=1.000
Molar volume = 2398.137 bohr**3/mol (214.007 cm**3/mol)
Recommended a0 for SCRF calculation = 5.34 angstrom ( 10.08 bohr)
Question (1): What's the shape of the box?
Question (2): How to calculate a0 from the molar volume?
It seems to me that the formula
(molar volume/Pi)^(1/3)+0.94 bohr
is used. But why?
The some of the output due to scrf=ipcm are
Max. Dist. Between Center of Nuclear Charge and Isosurface = 5.222190E+00
Min. Dist. Between Center of Nuclear Charge and Isosurface = 3.402845E+00
Total "Solvent Accessible Surface Area" of Solute = 2.467157E+02
Volume of Solute Cavity = 3.391144E+02
Question (3): What are the units of these values?
Question (4): Where can I find references that explains how to calculate
these values?
Thank you.
Shiang-Tai
Department of Chemical Engineering
University of Delaware
(O) (302) 831-6857
(H) (302) 368-8388
E-mail: stlin "at@at" udel.edu