Gaussian 03 Online Manual
Last update: 2 October 2006
Gaussian locates executables and creates scratch files in directories specified by several environment variables . However, the user is responsible for creating two of them:
g03root : Indicates the directory where the g03 directory resides (i.e., the directory above it).
GAUSS_SCRDIR : Indicates the directory which should be used for scratch files.
The Gaussian initialization files are responsible for initializing other aliases and environment variables as needed. All Gaussian users need to execute the appropriate Gaussian initialization file within their UNIX shell-specific initialization file. See this page for more details.
The environment variables created by g03.login and g03.profile include:
GAUSS_EXEDIR : Specifies the directories in which the Gaussian images are stored. By default it includes the main directory $g03root/g03 and several alternate directories.
GAUSS_ARCHDIR : Specifies the directory in which the main site-wide archive file is kept, and into which temporary archive files should be placed if the main archive is unavailable. It defaults to $g03root/g03/arch if unset.
G03BASIS : The directory which contains files specifying the standard Gaussian internally stored basis sets, as well as some additional basis sets in the form of general basis set input. This environment variable is provided for convenience and is designed for use with the @ include mechanism.
Scratch File Considerations
On UNIX systems, Gaussian generates unique scratch file names based on the process ID when no name has been specified by the user. This mechanism is designed to allow multiple Gaussian jobs to execute simultaneously using a common scratch directory.
Scratch files are deleted automatically when a job completes successfully or dies cleanly by default. However, scratch files are not deleted when a job is killed externally or otherwise terminates abnormally. Consequently, leftover files may accumulate in the scratch directory.
An easy method for avoiding excessive clutter is to have all users share a common scratch directory, and to have that scratch directory cleared at system boot time by adding an rm command to the appropriate system boot script (e.g., /etc/rc or one of the files under /etc/rc.d/rc3.d). If the NQS batch system is in use, clearing the scratch directory should also be done before NQS is started, ensuring that no jobs are using the directory when it is cleared.