Utility Programs

Description

Most utilities are available for both UNIX and Windows versions of Gaussian. However, be sure to consult the release notes accompanying the program for information pertaining to specific operating systems.

The GAUSS_MEMDEF environment variable may be used to increase the memory available to utilities. Its value should be set to the desired amount of memory. The default unit is words; the specified value can also be followed by a suffix indicating other units (e.g., GB for gigabytes). Each utility also has a -m option which performs the same function.

The following lists the available utilities and their functions (starred items are included on the Gaussian 16W Utilities menu):

c8616

Converts checkpoint files from previous program versions to Gaussian 16 format.

chkchk*

Displays the route and title sections from a checkpoint file.

cubegen*

Standalone cube generation utility.

cubman*

Manipulates Gaussian-produced cubes of electron density and electrostatic potential (allowing them to be added, subtracted, and so on).

formchk*

Converts a binary checkpoint file into an ASCII form suitable for use with visualization programs and for moving checkpoint files between different types of computer systems.

freqchk*

Prints frequency and thermochemistry data from a checkpoint file. Alternate isotopes, temperature, pressure and scale factor can be specified for the thermochemistry analysis.

freqmem

Determines memory requirements for frequency calculations.

gauopt

Performs optimizations of variables other than molecular coordinates.

ghelp

On-line help for Gaussian.

mm

Standalone molecular mechanics program.

newzmat*

Conversion between a variety of molecular geometry specification formats.

testrt*

Route section syntax checker and non-standard route generation.

unfchk*

Convert a formatted checkpoint file back to its binary form (e.g., after moving it from a different type of computer system).