scholarly journals Erratum: Rovibronic species, overall allowed species, and nuclear spin statistical weights for symmetric top molecules belonging to the Dnd and Dnh (n≤6) point groups [J. Chem. Phys. 73, 3952 (1980)]

1981 ◽  
Vol 74 (8) ◽  
pp. 4754-4754 ◽  
Author(s):  
Alfons Weber
Keyword(s):  
Nuclear Spin ◽  
Chem Phys ◽  
Point Groups ◽  
Symmetric Top Molecules

On the Role of Nuclear Spin Symmetry of Symmetric Top Molecules in Gas Phase Nuclear Magnetic Relaxation

1974 ◽  
Vol 52 (5) ◽  
pp. 387-395 ◽  
Author(s):  
B. C. Sanctuary
Keyword(s):  
Nuclear Spin ◽  
Magnetic Relaxation ◽  
Spin Symmetry ◽  
Nuclear Magnetic Relaxation ◽  
The Difference ◽  
Symmetric Top Molecules ◽  
Spin Species ◽  
Zero Frequency ◽  
Nuclear Magnetic

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.

Studies of the Jahn - Teller effect III. The rotational and vibrational spectra of symmetric-top molecules in electronically degenerate states

1961 ◽  
Vol 254 (1041) ◽  
pp. 259-294 ◽  
Keyword(s):  
Cross Sections ◽  
Oscillator Strengths ◽  
Infra Red ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Active Vibration ◽  
Point Groups ◽  
Irregular Spacing ◽  
Symmetric Top Molecules ◽  
Scattering Cross Sections

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.

Sign in / Sign up

Export Citation Format

Share Document