A General Procedure to Obtain Quantum Mechanical Charge and Bond Order Molecular Parameters

Byline: Ramon Carbo-Dorca (1), Patrick Bultinck (2) Keywords: Density analysis; Mulliken populations; atomic charges; bond orders; second order density; projection operators; expectation values Abstract: In an approach alternative to that of Mayer, a Hermitian operator is defined within the LCAO MO framework, which allows to obtain molecular charges and bond orders as expectation values of the first and second-order densities respectively. Such expectation values result to be nothing else than Mulliken's atom and bond populations. Thus, Mulliken populations appear to be non arbitrary condensed electron density partitions, obtained according to quantum mechanical usual procedures for molecular one and two electron observables. The theoretical simplicity of the outlined procedure can be easily extended in order to obtain the expectation values for higher-order electronic chemical bonds. Author Affiliation: (1) Institut de Quimica Computacional, Universitat de Girona, Girona, 17071, Catalonia, Spain (2) Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281, B-9000, Gent, Belgium Article History: Registration Date: 27/10/2004