Q-Chem

Availability and Restrictions

Q-Chem is available on the Oakley Cluster. The versions currently available at OSC are

VERSION OAKLEY ruby owens notes
4.0.1 X     Default version on Oakley prior to 09/15/2015
4.2.1 X      
4.2.2 X      
4.3 X      
4.3.1 X      
4.4 X      
4.4.1 X* X* X*  
4.4.1-openmp X X X  
*: Current default version

You can use module spider qchem  to view available modules for a given machine. Feel free to contact OSC Help if you need other versions for your work.

Access

The use of Q-Chem requires validation. In order to obtain validation, please contact OSC Help for further instruction.

Usage

Usage on Oakley

Set-up on Oakley

Q-Chem usage is controlled via modules. Load one of the Q-Chem modulefiles at the command line, in your shell initialization script, or in your batch scripts. To load the default version of Q-Chem module, use  module load qchem . To select a particular software version, use   module load qchem/version . For example, use  module load qchem/4.3   to load Q-Chem version 4.3 on Oakley. 

Examples

  • The root of the Q-Chem directory tree is /usr/local/qchem/ 
  • Example Q-Chem input files are in the samples subdirectory
  • Computational Chemistry Workshop materials are in /home/srb/workshops/compchem/qchem

Batch Usage on Oakley

When you log into oakley.osc.edu you are actually logged into a linux box referred to as the login node. To gain access to the mutiple processors in the computing environment, you must submit your job to the batch system for execution. Batch jobs can request mutiple nodes/cores and compute time up to the limits of the OSC systems. Refer to Queues and Reservations and Batch Limit Rules for more info.  Batch jobs run on the compute nodes of the system and not on the login node. It is desirable for big problems since more resources can be used.

Interactive Batch Session

For an interactive batch session one can run the following command:

qsub -I -l nodes=1:ppn=1 -l walltime=00:20:00

which requests one core ( -l nodes=1:ppn=1 ), for a walltime of 20 minutes ( -l walltime=00:20:00 ). You may adjust the numbers per your need.

Usage on Ruby

Set-up on Ruby

Q-Chem usage is controlled via modules. Load one of the Q-Chem modulefiles at the command line, in your shell initialization script, or in your batch scripts. To load the default version of Q-Chem module, use   module load qchem  . To select a particular software version, use    module load qchem/version  . For example, use   module load qchem/4.4.1    to load Q-Chem version 4.4.1 on Ruby. 

Examples

  • The root of the Q-Chem directory tree is /usr/local/qchem/ 
  • Example Q-Chem input files are in the samples subdirectory
  • Computational Chemistry Workshop materials are in /home/srb/workshops/compchem/qchem

Batch Usage on Ruby

When you log into ruby.osc.edu you are actually logged into a linux box referred to as the login node. To gain access to the mutiple processors in the computing environment, you must submit your job to the batch system for execution. Batch jobs can request mutiple nodes/cores and compute time up to the limits of the OSC systems. Refer to Queues and Reservations and Batch Limit Rules for more info.  Batch jobs run on the compute nodes of the system and not on the login node. It is desirable for big problems since more resources can be used.

Interactive Batch Session

For an interactive batch session one can run the following command:

qsub -I -l nodes=1:ppn=1 -l walltime=00:20:00

which requests one core (  -l nodes=1:ppn=1  ), for a walltime of 20 minutes (  -l walltime=00:20:00  ). You may adjust the numbers per your need.

 

 

Usage on Owens

Set-up on Owens

Q-Chem usage is controlled via modules. Load one of the Q-Chem modulefiles at the command line, in your shell initialization script, or in your batch scripts. To load the default version of Q-Chem module, use   module load qchem  . To select a particular software version, use    module load qchem/version  . For example, use   module load qchem/4.4.1    to load Q-Chem version 4.4.1 on Owens. 

Examples

  • The root of the Q-Chem directory tree is /usr/local/qchem/ 
  • Example Q-Chem input files are in the samples subdirectory
  • Computational Chemistry Workshop materials are in /home/srb/workshops/compchem/qchem

Batch Usage on Owens

When you log into owens.osc.edu you are actually logged into a linux box referred to as the login node. To gain access to the mutiple processors in the computing environment, you must submit your job to the batch system for execution. Batch jobs can request mutiple nodes/cores and compute time up to the limits of the OSC systems. Refer to Queues and Reservations and Batch Limit Rules for more info.  Batch jobs run on the compute nodes of the system and not on the login node. It is desirable for big problems since more resources can be used.

Interactive Batch Session

For an interactive batch session one can run the following command:

qsub -I -l nodes=1:ppn=1 -l walltime=00:20:00

which requests one core (  -l nodes=1:ppn=1  ), for a walltime of 20 minutes (  -l walltime=00:20:00  ). You may adjust the numbers per your need.

Q-Chem is a general purpose ab initio electronic structure program. Its latest version emphasizes Self-Consistent Field, especially Density Functional Theory, post Hartree-Fock, and innovative algorithms for fast performance and reduced scaling calculations. Geometry optimizations, vibrational frequencies, thermodynamic properties, and solution modeling are available. It performs reasonably well within its single reference paradigm on open shell and excited state systems. The Q-Chem Home Page has additional information.

Further Reading

General documentation is available from the Q-Chem Home page and in the doc subdirectories.

Service: