AOMix is a user-friendly software for the molecular orbital (MO) analysis. It calculates the MO compositions in terms of the constituent chemical fragments (you can specify them as atoms, groups of atoms, atomic orbitals, fragment molecular orbitals, groups of atomic orbitals, etc.) in the molecule or atom. AOMix automatically processes output files of multiple quantum-chemical packages (see the list below). AOMix also allows you to analyze chemical structure (bonding/antibonding nature of molecular orbitals) using overlap populations (total and per molecular orbital), valence indices, 2-center (Mayer, Lowdin, Wiberg, and bond-order symmetry components) and 3- and 4-center bond orders, charge decomposition analysis, CDA (total, per molecular orbital, per symmetry type), and condensed Fukui functions.

AOMix-S generates total, partial, and overlap population density-of-states (DOS) plots (these are available in line-plot and continuous-plot representations, see Figures 1, 2, and 3). Overlap population DOS plots are also refered in the literature as Crystal Orbital Overlap Population (COOP) diagrams.

A very important part of quantum chemical research is to interpret the results in terms of qualitative concepts. This software was developed to help in the analysis of the nature of the chemical bonding in molecular systems and to monitor changes in the electron density distribution upon the electron excitation. Let's say, there is a band in an absorption spectrum of a molecule or an ion at 400 nm which is assigned to a HOMO -> LUMO+2 electron excitation. What does it tell us about properties of this molecule/ion? What do we know about the nature of the corresponding excited state? What will happen with this molecule / ion after the photoexcitation? AOMix helps to answer these questions.

With AOMix and its AOMix-x modules, you can

• generate wave functions of multi-fragment molecular systems from converged fragment wave functions (any spin state and spin coupling);
• analyze molecular orbital compositions in terms of fragment atomic/molecular orbitals;
• evaluate bonding / antibonding contributions of molecular orbitals to the electronic structure (using overlap populations);
• calculate the amount of electron donation and back-donation between molecular fragments (using the charge decomposition analysis, CDA, implemented in the AOMix-CDA module);
• create total, partial and overlap population density-of-states plots;
• calculate condensed Fukui functions;
• evaluate charge transfer characters of electronic transitions;
• calculate the total and free valence index for atoms or fragments; and
• calculate the two-center (Mayer, Wiberg, Lowdin) and multi-center bond orders between molecular fragments.

You can refer to these publications to learn about the AOMix capabilities.

	The following procedures for the electron population analysis are available in the AOMix package:

1. Mulliken population analysis (MPA)
2. modified Mulliken population analysis (MMPA) (using AOMix-S)
3. C² population analysis (SCPA)
4. Lowdin population analysis (LPA) and other methods based on the S^a x P x S^1-a formula (using AOMix-L)
5. charge decomposition analysis (CDA) (using AOMix-CDA)

Supported operating systems	AOMix	AOMix-x
MS Windows 2000	+	+
MS Windows XP	+	+
MS Windows Vista	+	+
Red Hat Linux 9.0 and Fedora	in testing	in testing

	How to refer to the AOMix program in publications:

Compositions of molecular orbitals, overlap populations between molecular fragments, bond orders and density-of-states spectra were calculated using the AOMix program [1,2].

1. S. I. Gorelsky, AOMix: Program for Molecular Orbital Analysis, http://www.sg-chem.net/, University of Ottawa, 2007.
2. S. I. Gorelsky, A. B. P. Lever, J. Organomet. Chem. 2001, 635, 187-196.

	AOMix can process output files from the following quantum-chemistry packages (other packages can be also included)

	ADF (Scientific Computing & Modelling NV). AOMix has been tested with the following versions: ADF 2000.01, ADF 2002.03, ADF 2003.01, ADF 2004.01, and ADF 2005.01; please note that ADF calculations with core functions (do not confuse core functions with core orbitals!) cannot be processed by the current version of AOMix.
CNDO/INDO	CNDO/INDO (by J.R. Reimers, University of Sydney, Australia)
	The General Atomic and Molecular Electronic Structure System GAMESS from Iowa State University and PC GAMESS from Moscow State University. AOMix has been tested with the following versions: GAMESS-US 6, GAMESS VERSION = 12.
	Gaussian 98 and Gaussian 03 (Gaussian, Inc.)
	HyperChem 4.x-7.x (HyperCube, Inc.)
	Jaguar (Schrodinger, Inc.). AOMix has been tested with the following versions: Jaguar 3.5, Jaguar 4.1, Jaguar 4.2, Jaguar 5.0, Jaguar 5.5, and Jaguar 6.0
	MOPAC (J. J. P. Stewart, Fujitsu Limited) AOMix has been tested with the following versions: MOPAC2002 and MOPAC2007
	Q-Chem (Q-Chem, Inc.). AOMix has been tested with the following versions: Q-Chem 2.1 and Q-Chem 3.0
	Spartan (Wavefunction, Inc.). AOMix has been tested with the following versions: Spartan '02 and Spartan '03
Turbomole	Turbomole (Quantum chemistry group, University of Karlsruhe). using AOMix-prep.exe; AOMix-prep.exe has been tested with the following versions: TURBOMOLE V5-8-0
ZINDO	ZINDO (by M.C. Zerner, Quantum Theory Project, University of Florida; ZINDO is available in Cerius2 (Accelrys Inc.) and CAChe (CAChe Group, Fujitsu)); AOMix.exe has been tested with the following versions: ZINDO 98.1 and ZINDO 99.1

	How to obtain a copy of AOMix:

If you would like to obtain the AOMix program for yourself, your research group or company, please follow these instructions.

WWW.SG-CHEM.NET
All contents copyright © 1997-2008 S. I. Gorelsky
Last updated: April 2008