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APPROXIMATE QUANTUM MECHANICAL METHODS FOR LARGE MOLECULES
Author(s) -
Zerner Michael C.
Publication year - 1981
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.1981.tb50560.x
Subject(s) - excited state , perturbation theory (quantum mechanics) , ab initio , electronic structure , quantum , series (stratigraphy) , physics , molecule , quantum mechanics , chemistry , atomic physics , paleontology , biology
S ummary I discussed two approximate quantum mechanical methods that are particularly useful in examining the electronic structure of large molecular systems. The first method mentioned was the Zero Differential Overlap theory, which has been developed and used quite successfully in describing electronic spectroscopy and the properties of excited states. Most recently, this theory has been extended to include elements of the first transition series. I discussed some details of the system that suggest that all one‐centered integrals must be included for accurate predictions. Results for ferrocene and for a model oxyheme complex demonstrate that the balance between charge transfer, d‐d, and ligand‐ligand excitations, so difficult to obtain in ab initio work, is easily reached by this theory. The second method I discussed was the localized bond configuration interaction method, which is especially useful when the total energy is the principal property of interest, as, for example, in conformation studies. This method has now been implemented to high order in perturbation theory, but it still executes as an N 3 procedure, where N is the number of bonds.