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Generalized double exponential potential functions for diatomic molecules
Author(s) -
Graves John L.
Publication year - 1997
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/(sici)1097-461x(1997)65:1<1::aid-qua1>3.0.co;2-#
Subject(s) - diatomic molecule , exponential function , double exponential function , physics , computational chemistry , molecule , chemistry , atomic physics , statistical physics , quantum mechanics , mathematics , mathematical analysis
Two variants of the double exponential potential function and their virial modifications are proposed and tested. The first in reduced variables is F ( t )= e − mt {[ m ( m 2 −1) −1/2 −1]exp[−( m 2 −1) 1/2 t ]−[ m ( m 2 −1) −1/2 +1]exp[( m 2 −1) 1/2 t ]} where t =κ s =κ( R − R e ))/ R e , κ is a scaling constant, and m is a parameter. The second is G ( t )= e − mt { e − mt −exp[( m 2 −1) 1/2 t ]+exp[−( m 2 −1) 1/2 t ]}. For m <1, F ( t ) and G ( t ) are expressible in terms of trigonometric functions. A new procedure [multiplication by e s /(1+ s )] is illustrated that modifies potential functions so that they necessarily satisfy the molecular virial theorem. The generalized double exponential functions generate scaled first and second Dunham coefficients that well describe the experimental results for both ground and excited states. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 65 : 1–8, 1997