# Software - Quantum Mechanics

### Contents

## Gaussian

Gaussian is used to study molecules and reactions of definite or potential interest, including both stable species and compounds which are difficult or impossible to observe experimentally: short-lived intermediates, transition structures, etc. It can predict energies, molecular structures, vibrational frequencies-along with the numerous molecular properties that are derived from these three basic computation types-for systems in the gas phase and in solution, and it can model them in both their ground state and excited states.

#### Usage Instructions:

**Gaussian '16** and **GaussView 6** are available via Lop. See https://answers.uillinois.edu/scs/scs-clusters for access information and below tutorials for help in using Gaussian.

#### Tutorials:

Tutorial - Quantum Chemistry - Intro to Gaussian I

Tutorial - Quantum Chemistry - Intro to Gaussian Part II

Tutorial - Quantum Chemistry - Simulating Vibrationally-resolved Electronic Spectra Using Gaussian

Tutorial - Quantum Chemistry - Determining the pKa of Simple Molecules Using Gaussian 2016

Tutorial - Quantum Chemistry with Gaussian using GaussView

## GAMESS

Gordon Group, Iowa State University

GAMESS is a program for *ab initio* quantum chemistry that can compute wave functions ranging from RHF, ROHF, UHF, GVB, and MCSCF, with CI and MP2 energy corrections available for some of these. Analytic gradients are available for these SCF functions, for automatic geometry optimization, transition state searches, or reaction path following. Computation of the energy hessian permits prediction of vibrational frequencies. A variety of molecular properties, ranging from simple dipole moments to frequency dependent hyperpolarizabilities may be computed.

## Jaguar

Jaguar is an *ab initio* quantum mechanics package for both gas and solution phase simulations.

Jaguar is a module of the Schrödinger computational platform, which is available to the University's research community as part of SCS's Scientific Software Program. Please see the Program's page for pricing and access instructions.

## Spartan

This program is a molecular modeling package that specializes in electronic structure calculations, including *ab initio*, density functional theory, semi-empirical, molecular mechanics, similarity analysis, conformational analysis, and property calculations including QSAR.