skip to main content

SciTech ConnectSciTech Connect

Title: Rovibrational spectroscopy using a kinetic energy operator in Eckart frame and the multi-configuration time-dependent Hartree (MCTDH) approach

For computational rovibrational spectroscopy the choice of the frame is critical for an approximate separation of overall rotation from internal motions. To minimize the coupling between internal coordinates and rotation, Eckart proposed a condition [“Some studies concerning rotating axes and polyatomic molecules,” Phys. Rev. 47, 552–558 (1935)] and a frame that fulfills this condition is hence called an Eckart frame. A method is developed to introduce in a systematic way the Eckart frame for the expression of the kinetic energy operator (KEO) in the polyspherical approach. The computed energy levels of a water molecule are compared with those obtained using a KEO in the standard definition of the Body-fixed frame of the polyspherical approach. The KEO in the Eckart frame leads to a faster convergence especially for large J states and vibrationally excited states. To provide an example with more degrees of freedom, rotational states of the vibrational ground state of the trans nitrous acid (HONO) are also investigated.
Authors:
;  [1] ;  [2] ;  [3]
  1. Theoretische Chemie, Ruprecht-Karls-Universität, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany)
  2. CNRS, Laboratoire de Chimie Physique (UMR 8000), Université Paris-Sud, F-91405 Orsay (France)
  3. CTMM, Institut Charles Gerhardt (UMR 5232), CC 1501, Université Montpellier II, F-34095 Montpellier Cedex 05 (France)
Publication Date:
OSTI Identifier:
22308393
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 11; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; APPROXIMATIONS; COUPLING; GROUND STATES; KINETIC ENERGY; MOLECULES; NITROUS ACID; ROTATION; ROTATIONAL STATES; SPECTROSCOPY; TIME DEPENDENCE