MOLECULAR CHARGE-DENSITY ANALYSIS

It is proposed to analyse the first-order reduced density matrix of a molecular wave function in terms of the first-order reduced density ma trices of different states of the constituent atoms. With this an unam biguous partitioning of the molecular charge distribution in terms of the atomic charge distributions is obtained. Simple practical formulae are derived, such that in many ab initio molecular wave function calc ulations the analysis proposed can be carried out routinely. The resul ts obtained should be useful for the interpretation of molecular wave functions in terms of their atomic constituents, as well as for the de termination of atomic form factors to be used in X-ray molecular struc ture determination. Some simple examples are given, and the results ob tained are compared with those obtained using other methods of analysi s.