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ChemOffice.Com - CambridgeSoft

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Chapter 12 :<br />

<strong>Com</strong>putations<br />

GAMESS Overview<br />

The General Atomic and Molecular Electronic<br />

Structure System (GAMESS) is a general ab initio<br />

quantum chemistry package maintained by the<br />

Gordon research group at Iowa State University. It<br />

computes wavefunctions using RHF, ROHF,<br />

UHF, GVB, and MCSCF. CI and MP2 energy<br />

corrections are available for some of these.<br />

GAMESS is a command-line application, which<br />

requires a user to type text-based commands and<br />

data. Chem3D serves as a front-end graphical user<br />

interface (GUI), allowing you create and run<br />

GAMESS jobs from within Chem3D.<br />

Installing GAMESS<br />

You must download and install the GAMESS<br />

application separately.<br />

You can download the GAMESS application and<br />

documentation from the following web site:<br />

http://www.msg.ameslab.gov/GAMESS/<br />

GAMESS.html<br />

GAMESS<br />

Minimize Energy<br />

To perform a GAMESS Minimize Energy<br />

computation on a model:<br />

1. From the Calculations menu, point to Gamess<br />

and choose Minimize Energy.<br />

The Minimize Energy dialog box appears with<br />

the Theory tab displayed.<br />

2. Use the tabs to customize your computation.<br />

See the following sections for details.<br />

3. Click Run.<br />

The Theory Tab<br />

Use the Theory tab to specify the combination of<br />

basis set and particular electronic structure theory.<br />

By default, this tab is optimized for setting up<br />

ab initio computations.<br />

For more detailed information, see the $BASIS<br />

section of the GAMESS documentation.<br />

<strong>ChemOffice</strong> 2005/Chem3D GAMESS <strong>Com</strong>putations • 201<br />

Installing GAMESS

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