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Title: Automatic computer procedure for generating exact and analytical kinetic energy operators based on the polyspherical approach: General formulation and removal of singularities

We present new techniques for an automatic computation of the kinetic energy operator in analytical form. These techniques are based on the use of the polyspherical approach and are extended to take into account Cartesian coordinates as well. An automatic procedure is developed where analytical expressions are obtained by symbolic calculations. This procedure is a full generalization of the one presented in Ndong et al., [J. Chem. Phys. 136, 034107 (2012)]. The correctness of the new implementation is analyzed by comparison with results obtained from the TNUM program. We give several illustrations that could be useful for users of the code. In particular, we discuss some cyclic compounds which are important in photochemistry. Among others, we show that choosing a well-adapted parameterization and decomposition into subsystems can allow one to avoid singularities in the kinetic energy operator. We also discuss a relation between polyspherical and Z-matrix coordinates: this comparison could be helpful for building an interface between the new code and a quantum chemistry package.
Authors:
;  [1] ;  [2] ; ;  [3] ;  [4]
  1. CNRS, Laboratoire de Chimie Physique (UMR 8000), Université Paris-Sud, F-91405 Orsay (France)
  2. Institut de la Matière Condensée et des Nanosciences, Université Catholique de Louvain, Chemin du Cyclotron 2, 1348-Louvain-la-Neuve, Belgium and Laboratoire de Chimie Physique (UMR 8000), Université Paris-Sud, F-91405 Orsay (France)
  3. CTMM, Institut Charles Gerhardt (UMR 5232-CNRS), CC 1501, Université de Montpellier II, F-34095 Montpellier cedex 05 (France)
  4. Theoretische Chemie, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany)
Publication Date:
OSTI Identifier:
22220290
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 139; Journal Issue: 20; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CARTESIAN COORDINATES; DECOMPOSITION; KINETIC ENERGY; REACTION KINETICS