Rovibronic species, overall allowed species, and nuclear spin statistical weights for symmetric top molecules. II. Point groups Cnv and Cnh (n≤6)

1982 ◽  
Vol 76 (7) ◽  
pp. 3694-3698 ◽  
Author(s):  
Alfons Weber
1974 ◽  
Vol 52 (5) ◽  
pp. 387-395 ◽  
Author(s):  
B. C. Sanctuary

For symmetric top molecules the role of nuclear spin symmetry is included in the derivation of the nuclear magnetic relaxation rate. It is assumed that this is dominated by a spin-rotation mechanism. Of the three nuclear spin species which exist for ZX3Y' symmetric tops, it is found that the "zero frequency" K = −1 to +1 term results in two of the species relaxing with a different rate from the third. The difference, which allows a direct NMR evaluation of the relative values of [Formula: see text] and [Formula: see text], is enhanced at low temperatures.


We have developed the physical theory required for interpreting the infra-red, Raman and microwave spectra of molecules in orbitally degenerate electronic states in which spin-orbit coupling is unimportant. Formulae are obtained which relate the oscillator strengths and scattering cross-sections to the electrical and mechanical properties of the molecule, and group theoretical selection rules are derived and applied to the common point groups. Among other results we find: ( a )that in an electronically degenerate state a molecule may exhibit a dipole moment which would be symmetry-forbidden if the electronic state were non-degenerate, ( b ) that certain lines in the Raman spectrum may have depolarization ratio greater than f, because of the possibility of pseudo-vector scattering, and ( c ) that in both the infra-red and Raman spectra a Jahn-Teller active vibration may give rise to overtones of extremely high intensity but irregular spacing.


2019 ◽  
Vol 123 (29) ◽  
pp. 6160-6174 ◽  
Author(s):  
Veronika Horká-Zelenková ◽  
Georg Seyfang ◽  
Peter Dietiker ◽  
Martin Quack

1997 ◽  
Vol 91 (5) ◽  
pp. 897-907 ◽  
Author(s):  
SHEELA KIRPEKAR ◽  
THOMAS ENEVOLDSEN ◽  
JENS ODDERSHEDE ◽  
WILLIAM RAYNES

1999 ◽  
Vol 97 (6) ◽  
pp. 821-824 ◽  
Author(s):  
Per Jensen, P. R. Bunker
Keyword(s):  

1982 ◽  
Vol 43 (7) ◽  
pp. 1049-1058 ◽  
Author(s):  
M. Goldman ◽  
J.F. Jacquinot

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