ZINDO

ZINDO is a semi-empirical quantum chemistry method used in computational chemistry. It is a development of the INDO method. It stands for Zerner's Intermediate Neglect of Differential Overlap, as it was developed by Michael Zerner. [ M. Zerner, Reviews in Computational Chemistry, Volume 2, Eds. K. B. Lipkowitz and D. B. Boyd, VCH, New York, 313, (1991) ] Unlike INDO which was really restricted to organic molecules and those containing the atoms B to F, ZINDO covers a wide range of the periodic table, even including the rare earth elements. There are two distinct versions of the method:-

* ZINDO/1 - for calculating ground state properties such as bond lengths and bond angles.
* ZINDO/S (sometimes just called INDO/S) - for calculating excited states and hence electronic spectra.

The original program from the Zerner group is not widely available but the method is implemented in HyperChem and, in part, in Gaussian.

A major complaint against ZINDO in particular is that while it could reproduce the low lying spectra of larger polyenes and some organo-metallic compounds, it lacked a consistent parameterization. To obtain good results, it had been frequently necessary to fit the parameters to a given molecule, thereby reducing its generality and predictive capacity. In contrast, ab initio packages, such as GAUSSIAN, gained popularity because they would always produce the same results for a given input, even if the results were sometimes inaccurate.

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