INDO and INDOS

The G and L values may be regarded as free parameters, but in practice they can be estimated from spectroscopic data. When the atomic valence orbitals include d and f functions, the number of unique integrals increases considerably, and the estimation of appropriate values from spectroscopy becomes considerably more complicated. 

System (ground state) State (transition) INDO/S prediction Experiment 

The first general parameterization to be reported by Dewar and co-workers was a third-generation modified INDO model (MINDO/3 Bingham, Dewar, and Lo, 1975). Some of the specific modifications to the INDO framework included the use of different t exponents in s and p type STOs on the same atom, the definition of pair parameters /Iab between two atoms A and B that were not averages of atomic parameters (actually, four such parameters 

The performance of the MINDO/3 model was impressive overall. The mean absolute error in predicted heats of formation was 11 kcal/mol (all molecules), the corresponding 

One effect of the greater flexibility inherent in the INDO scheme is that valence bond angles are predicted with much greater accuracy than is the case for CNDO. Nevertheless, overall molecular geometries predicted from INDO tend to be rather poor. However, if a good molecular geometry is available from some other source (ideally experiment) the INDO method has considerable potential for modeling the UV/Vis spectroscopy of the compound because of its better treatment of one-center electronic interactions. 

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INDO, and INDO/S methods. MOPAC (J. J. P. Stewart,/. Comp.-Aided Mol. Design, 4, 1 (1990) home.att.net/ mrmopac/) has the MINDO/3, MNDO, AMI, and PM3 methods and is available in workstation and IBM-PC-compatible versions. MND094 (www.oxmol.co.uk/prods/unichem/cap/) has the AMI, PM3, MNDO, MINDO/3, and MNDO/d methods. AMPAC 6.0 (www.semichem.com/) has the SAMI, AMI, PM3, MNDO, and MNDO/d methods. 

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