Gaussian offers many pre-defined solvents, which are specified as keywords to the SCRF=Solvent option. In order to specify a solvent not included in this set, it is generally only necessary to specify the value of its dielectric constant ε using additional input to the SCRF keyword, as in this example:
# B3LYP/6-311+G(2d,p) SCRF(Read) Defining a solvent for IEFPCM 0 1 molecule specification Eps=28.5 PCM input section final blank line
For the SMD method, additional parameters are required. These are the 7 items needed to define a solvent for SMD:
|SCRF= Read Parameter
|Dielectric constant at 298 K. Note that dielectric constant is also called the relative permittivity.
|The square of the index of refraction at optical frequencies (293 K). This is sometimes called .
|Abraham’s hydrogen bond acidity. In particular, in Abraham’s notation this is called .
|Abraham’s hydrogen bond basicity. In particular in Abraham’s notation this is called .
|γ = γm/γo, where γm is macroscopic surface tension at a liquid-air interface at 298 K,
|and γo is 1 cal mol-1Å-2. Conversion factor: 1 dyne/cm = 1.43932 cal mol-1 Å-2
|Aromaticity: fraction of non-hydrogenic solvent atoms that are aromatic carbon atoms.
|Electronegative halogenicity: fraction of non-hydrogenic solvent atoms that are F, Cl, or Br.
This example shows the SCRF additional input keywords needed to define the solvent bromobenzene:
|# B3LYP/6-31G(d) 5D SCRF(SMD,Solvent=Generic,Read)
|Input section for PCM keywords
|Blank line terminates PCM input
Last updated on: 26 June 2018.