Premium
Molecular quantum theory: Separable electronuclear wave functions and vibronic states—A generalized diabatic approach
Author(s) -
Tapia O.
Publication year - 2004
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.20035
Subject(s) - diabatic , hamiltonian (control theory) , wave function , ansatz , quantum mechanics , physics , superposition principle , operator (biology) , potential energy , quantum , chemistry , mathematics , adiabatic process , mathematical optimization , biochemistry , repressor , transcription factor , gene
The linear superposition principle is used to represent chemical and physical processes. A quantum state representation is obtained for model molecular systems. An exact Hamiltonian is first introduced and thereafter approximated by a sum of Coulomb Hamiltonian, electron–phonon (e–ph), relativistic effects, and coupling to external fields. A sharp separability ansatz is used to study the Coulomb Hamiltonian first; the electronic part is fully represented in Hilbert space ( q space); a background of positive charge replaces nuclei in real space (ξ space). This QC model leads to diabatic electronic functions and diabatic potential energy (DPE) surfaces in real space. Next, the nuclear masses are introduced via a kinetic energy operator and added to the DPEs. The attractor property of the diabatic electronic functions is used to study mass fluctuation regimes. Fluctuations, if quantized, lead to the Q 2 C model; mass dynamics takes place in real space. The set of product functions {ϕ j ( q )ζ jl (ξ)} provides a base to represent arbitrary electronic states. In this context, the linear superposition principle is naturally introduced. The formulation of chemical reactions, pump–probe experiments and a detailed study of H + 2are topics examined from the present perspective. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004