Studies in vibrational absorption intensities

Steele, D.; Wheatley, W.

doi:10.1016/0022-2852(69)90220-3

Cited by 8 publications

(1 citation statement)

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“…The infrared fundamental intensities of benzene and hexafluorobenzene were measured in the gas phase some years ago by several research groups. − Interest originally centered on the interpretation of the infrared intensity parameters in terms of CH and CF bond moments as well as on an electron rehybridization moment of the ring π electrons. Out-of-plane deformations were expected to be strongly affected by rehybridization moments, whereas in-plane deformations were not.…”

Section: Introductionmentioning

confidence: 99%

Quantum Theory Atoms in Molecules Charge−Charge Flux−Dipole Flux Models for the Infrared Intensities of Benzene and Hexafluorobenzene

et al. 2009

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The infrared fundamental intensities of benzene and hexafluorobenzene have been calculated at the MP2/6-311++G(3d,3p) level. The theoretical values are in excellent agreement with the averaged experimental C(6)H(6) results having a rms error of 15.3 km mol(-1). However, the theory badly underestimates the CF stretching and ring deformation intensities of C(6)F(6) having an overall rms error of 141 km mol(-1). The theoretical results confirm the dipole moment derivative signs previously attributed on the basis of the comparison of C(6)H(6) and C(6)D(6) derivatives and semiempirical molecular orbital results. A quantum theory atoms in molecules charge-charge flux-dipole flux interpretation of the theoretical results shows that electronic density changes for out-of-plane vibrations can be explained using a simple bond moment-rehybridization moment model proposed many years ago. However, these changes were found to be much more complicated for the in-plane vibrations involving important charge flux and dipole flux contributions for both molecules as well as contributions from the displacement of equilibrium atomic charges for hexafluorobenzene.

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