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Last updated: The most current version of AOMix: January 19, 2010 6.46 | software updates and changes | software download | feedback
Events: March 20, 2009: the presentation about the AOMix software at Q-Chem workshop at Pittsburgh Supercomputing Center
AOMix-CDA is a part of the AOMix package. It
- generates a wave function of a multi-fragment molecular system from the fragment wave functions (refer to APPENDIX II of the AOMix manual for details);
- performs the analysis of MO compositions in terms of fragment molecular orbitals (FOs). The number of fragments can be from 1 (in this case, the analysis is performed relative to a user-defined, reference electronic state, see for example [PDF]) up to 4000. The program is able to treat all spin-coupling cases:
- ferromagnetic coupling (alpha-spin FOs of Fragment X couple with alpha-spin FOs of Fragment Y, beta-spin FOs of Fragment X couple with beta-spin FOs of Fragment Y)
- anti-ferromagnetic coupling (alpha-spin FOs of Fragment X couple with beta-spin FOs of Fragment Y, beta-spin FOs of Fragment X couple with alpha-spin FOs of Fragment Y)
- any possible combination of ferromagnetic and anti-ferromagnetic for a case of multiple fragments;
- calculates the amount of electron donation between fragments (the charge decomposition analysis, CDA),
- calculates fragment orbital populations in a molecule,
- calculates atomic orbital populations in a molecule, in non-interacting fragments (or a reference molecule if the number of fragments is 1) and the difference in AO populations,
- prints the LCFO-MO coefficient matrix and the FO overlap matrix,
- can be used for energy decomposition analysis (EDA, Morokuma-Ziegler), for Gaussian 98/03/09 calculations; and
- generates the plot data for orbital interaction diagrams (see the examples below).
With AOMix-CDA, you can analyze the electronic structure and bonding in molecules in great detail, calculate charge transfer (CT) and electronic polarization (PL) contributions, evaluate the sigma- and pi- bonding interactions, etc. [PDF file]
Here is an example of the AOMix-CDA output:
It is the charge decomposition analysis of the BH3CO molecule (fragment 1 is BH3 and fragment 2 is CO, HyperChem AM1 calculations). According to the analysis, the charge donation from CO to BH3 is 0.417 electrons and the back-donation from BH3 to CO is 0.143 electrons).AOMix-CDA also sets up data files for plotting the MO interaction diagrams, see Figures below.
Similar donation/back-donation charges (0.47 and 0.18 electrons respectively) are obtained from Gaussian 03 calculations at the HF/6-31G* level:
Advantanges of the AOMix-CDA program:
- AOMix-CDA can handle more than two molecular fragments (up to 99 fragments). This allows the analysis of more complex molecular systems (such as bridged metal complexes L1-M1-bridge-M2-L2, for example) than just simple binary donor-acceptor complexes;
- AOMix-CDA can be used for spin-restricted, spin-unrestricted and "mixed" (spin-restricted and spin-unrestricted) calculations.
Here is an example of the AOMix-CDA calculation with 3 fragments where the whole molecule and the 1st fragment are treated at the spin-unrestricted DFT level (open-shell species), and the 2nd and 3rd fragments are treated at the spin-restricted DFT level (closed-shell species):
The orbital interaction diagram (using Gaussian 03 and AOMix-CDA at the B3LYP/TZVP level) of the Cu(HB(3,5-iPr2pz)3) and thiolate SC6F5 fragments forming the [Cu(HB(3,5-iPr2pz)3)(SC6F5)] complex. p (a2 symmetry) orbitals are shown in blue color and s orbitals (a1 symmetry) are in red.
For more details, check the following publications:
Spectroscopic and DFT Investigation of [M(HB(3,5-iPr2pz)3)(SC6F5)], (M = Mn, Fe, Co, Ni, Cu and Zn) Model Complexes: Periodic Trends in Metal-Thiolate Bonding.
S. I. Gorelsky, L. Basumallick, J. Vura-Weis, R. Sarangi, B. Hedman, K. O. Hodgson, K. Fujisawa, E. I. Solomon
Inorg. Chem., 2005, 44, 4947-4960 [PDF].Metal-thiolate bonds in bioinorganic chemistry
E. I. Solomon, S. I. Gorelsky, A. Dey
J. Comput. Chem., 2006, 27, 1415-1428 [PDF].
The orbital interaction diagram (computed using Gaussian 03 and AOMix-CDA at the B3LYP/LanL2DZ level) of the Ru(NH3)2Cl2 and BQDI fragments forming the [Ru(NH3)2Cl2(BQDI)] complex.
In this complex, the BQDI-to-Ru donation is produced by the interactions involving fragment orbitals of a1 and b2 symmetries, namely, HOFO-1 and HOFO-2 of the bqdi ligand and the LUFO and LUFO+1 of the Ru fragment (see the above figure, black and red lines). The Ru-to-BQDI back-donation is produced by the orbital interaction between the HOFO of the Ru fragment and the LUFO of the BQDI ligand of b1 symmetry. The ECDA analysis shows that the LUMO of the the complex is an anti-bonding combination of 62 % LUFO(bqdi) and 33 % HOFO(Ru). The corresponding bonding orbital (HOMO-1 of the complex) is formed by 61% HOFO(Ru) and 29% LUFO(bqdi). These orbital contributions indicate the strong back-bonding interaction and account for a transfer of ~0.7 e- from the Ru fragment to the BQDI ligand. [PDF].
Here is another example of the AOMix-CDA output: the orbital interaction diagram (computed using Gaussian 03 at the B3LYP/TZVP level) of two methylidyne (CH) radicals (in the quartet spin state, S=4) forming the a linear acetelene molecule HCCH (alpha-spin orbitals are shown in blue, beta-spin orbitals are shown in red color):
The examples of ADF 2005, Gaussian 03 (Gaussian 98 examples are identical to those from Gaussian 03), Jaguar 5.5 and HyperChem 5.0 input files for AOMix-CDA and the corresponding AOMix-CDA output files can be downloaded by users at this link.
Since the AOMix-CDA program use output files from the main program (AOMix.exe), AOMix-CDA can be used for post-processing of quantum-chemical packages which are usable with AOMix: ADF, CNDO/INDO, GAMESS(US), Gaussian 98, Gaussian 03, Gaussian 09, HyperChem 4.x-7.x, Jaguar, MOPAC, Q-Chem, Spartan, ZINDO (other packages can be also included).
