Gaussian 09 Job Types

The route section of a Gaussian 09 input file specifies the type of calculation to be performed. There are three key components to this specification:

The following table lists the job types available in Gaussian 09:

In general, only one job type keyword should be specified. The exceptions to this rule are:

When no job type keyword is specified within the route section, the default calculation type is usually a single point energy calculation (SP). However, a route section of the form: method2/basis2 // method1/basis1 may be used to request an optimization calculation (at method1/basis1) followed by a single point energy calculation (at method2/basis2) at the optimized geometry. For example, the following route section requests a B3LYP/6-31G(d) geometry optimization followed by a single point energy calculation using the CCSD/6-31G(d) model chemistry:

# CCSD/6-31G(d)//B3LYP/6-31G(d) Test

In this case, the Opt keyword is optional and is the default. Note that Opt Freq calculations may not use this syntax.

Predicting Molecular Properties

The following table provides a mapping between commonly-desired predicted quantities and the Gaussian 09 keywords that will produce them:


Last updated on: 9 Jun 2009