Anharmonic potential functions of polyatomic molecules. IV. Formulae for the zero-order frequencies

1958 ◽  
Vol 23 (10) ◽  
pp. 1852-1863 ◽  
Author(s):  
J. Plíva
Keyword(s):  
Polyatomic Molecules ◽  
Zero Order ◽  
Potential Functions ◽  
Anharmonic Potential

Anharmonic potential functions of polyatomic molecules

1967 ◽  
Vol 23 (3) ◽  
pp. 331-342 ◽  
Author(s):  
J. Plíva ◽  
V. Špirko ◽  
D. Papoušek
Keyword(s):  
Polyatomic Molecules ◽  
Potential Functions ◽  
Anharmonic Potential

CALCULATION OF SELECTED HIGHLY EXCITED VIBRATIONAL STATES OF POLYATOMIC MOLECULES BY THE DAVIDSON ALGORITHM

2003 ◽  
Vol 02 (04) ◽  
pp. 609-620 ◽  
Author(s):  
FABIENNE RIBEIRO ◽  
CHRISTOPHE IUNG ◽  
CLAUDE LEFORESTIER
Keyword(s):  
Energy Levels ◽  
Normal Modes ◽  
Chem Phys ◽  
Polyatomic Molecules ◽  
Zero Order ◽  
Basis Set ◽  
Vibrational States ◽  
Diagonalization Method ◽  
Davidson Algorithm ◽  
High Overtone

We described an improved version of a modified Davidson scheme previously introduced (F. Ribeiro, C. Iung and C. Leforestier, Chem. Phys. Lett.362, 199 (2002)), aimed at computing highly excited energy levels of polyatomic molecules. The key ingredient is a prediagonalization-perturbation step performed on a subspace of a curvilinear normal modes basis set (including diagonal anharmonicities). The efficiency of the method is demonstrated by computing the lowest 350 vibrational states of A′ symmetry of the HFCO molecule. Also shown is the possibility to restrict the calculation to selected energy levels, based on their zero-order description. This State Filtered Diagonalization method is illustrated on a high overtone (7ν5) of the OCF bend, and on the few energy levels (20) which have been experimentally assigned up to 5000 cm -1 of excitation energy.

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