Determinable parameters of the effective rotational Hamiltonians for excited vibrational states of semirigid symmetric top molecules of C4v, D4, D2h, andD2d symmetry

1989 ◽  
Vol 54 (12) ◽  
pp. 3107-3116
Author(s):  
Kamil Sarka ◽  
Dušan Papoušek
Keyword(s):  
Symmetry Axis ◽  
Energy Levels ◽  
Contact Transformation ◽  
Centrifugal Distortion ◽  
Vibrational States ◽  
Fourfold Symmetry ◽  
Vibration Rotation ◽  
Symmetric Top Molecules ◽  
Rotation Energy ◽  
General Method

A general method is described for obtaining the S functions which in the contact transformation of the vibration-rotation Hamiltonian of semirigid molecules with the fourfold symmetry axis eliminate the rotational and vibrational l-type operators and the Δk = ±4 centrifugal distortion operators from the λH1 terms of the expanded Hamiltonian. Explicit expressions are given for the vibration-rotation energy levels with independent effective spectroscopic parameters. Expressions are also given for the splittings of energy levels with essential resonances.

A vibration-rotation band of monodeuteromethane

1953 ◽  
Vol 216 (1125) ◽  
pp. 143-152 ◽  
Keyword(s):  
Energy Levels ◽  
High Dispersion ◽  
Vibration Band ◽  
Hydrogen Atoms ◽  
Vibrational States ◽  
Fundamental Vibration ◽  
Type Band ◽  
Vibration Rotation ◽  
Two Sides ◽  
Very High

The fundamental vibration band of monodeuteromethane near 4-5 μ , connected with the stretching of the C—D bond, has been reinvestigated with very high dispersion. It provides a good example of well-resolved parallel-type band structure of a symmetric top molecule in which the K splitting of P and R lines is clearly seen. Alternations of intensity are also found in accordance with the nuclear spin of the three hydrogen atoms. The rotational constants B 0 and B 1 have been determined, giving r 0 (C—H) = 1.0924Å. The centrifugal stretching coefficient D J and its variation in the different vibrational states have also been measured. Analysis of the K splitting of the R and P lines reveals an anomaly between the sets on the two sides of the band origin, which seems to suggest that some unforeseen molecular interaction is neglected in the method at present accepted for calculating the molecular rotational energy levels.

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