title: Topography of molecular scalar fields. II. An appraisal of the hierarchy principle for electron momentum densities.
abstract: The previously observed hierarchy principle for nondegenerate critical points (CPs) of the electron momentum density (EMD) of molecules [Kulkarni, Gadre, and Pathak, Phys. Rev. A. 45, 4399 (1992)] is verified at a reliable level of theory. Application of Morse inequalities and the Poincare-Hopf relation to EMD leads to some rigorous results viz (i) for total number of CPs, NCP=3,7,11,15, ...there must be either a (3,+3) or a (3,-1) CP at the center of symmetry, (ii) for N(CP)=1,5,9,13, ...there must be either a (3,-3) or a (3,+1) CP at the center of symmetry. A single directional maximum on every ray, starting from p=0 has been observed for all the test molecules and is suggested as a working topographical principle in p space. This working principle is shown to satisfy the sufficiency condition for the hierarchy principle.
authors.affiliation: Department of Chemistry, University of Pune, Pune 411 007, India.
authors.forename: P
authors.initials: P
authors.lastname: Balanarayan
authors.forename: Shridhar R
authors.initials: SR
authors.lastname: Gadre