Erratum: The benzene ground state potential surface. II. Harmonic force field for the planar vibrations [J. Chem. Phys. <b>8</b>
                  <b>7</b>, 2564 (1987)]

Intense field resonance Raman scattering by a molecular continuum: A coupled equations study J. Chem. Phys. 77, 3867 (1982); 10.1063/1.444340 Vibrational Raman scattering from excited triplet state chrysene by timeresolved resonance Raman spectroscopy Resonance Raman scattering in iodobenzene is studied for excitation in the region 219-233 nm (B IAI -X IAI ). There is a rich Raman spectrum containing strong fundamentals of ringbased modes and the C-I stretch. On resonance, overtones and combination bands of most modes are strongly enhanced. The modulation of the C-I stretch activity as a function of wavelength is interpreted in terms of the initial dynamical evolution of the molecule in the excited state. A normal mode analysis is also made of the ground-state planar modes of iodobenzene in order to correlate the observations with the resonance Raman spectra in benzene.

Section: Normal Mode Analysismentioning

confidence: 53%

“…3 and 4 ofOzkabak and Goodman. 17 There are exceptions to this one-to-one mapping, however. From the a l correlation diagram, it is seen that V 7 in C 6 Hs I descends toward Vg and V9 on the extreme right, I I I I I I I I I I I I I I I lie (a 1 )…”

Section: Normal Mode Analysismentioning

confidence: 99%

Spectroscopy and dynamics of resonance Raman scattering by iodobenzene excited in the B continuum

O’Brien

Kittrell

Kinsey

et al. 1992

“…This theory is based upon force constants generated and scaled by ab initio calculations, an approach accepted in recent years as valid for generating theoretical force constants. 16 They reported the lowest frequency B 1 mode at 95 cm Ϫ1 . 11 Considering that lines C and D overlap at 0.62 kbar at 96.91 cm Ϫ1 , the agreement is embarrassingly good.…”

Section: B Polarization Studymentioning

confidence: 98%

High pressure studies of the acridine/fluorene photoreaction: Vibration assisted tunneling

Chan

Dernis

Wong

et al. 1995

Articles you may be interested inThe highpressure range of the reaction of CH(2Π) with N2 High pressure range of addition reactions of HO. II. Temperature and pressure dependence of the reaction HO+COHOCO→H+CO2 High pressure range of the addition of HO to HO, NO, NO2, and CO. I. Saturated laser induced fluorescence measurements at 298 K High pressure studies of a hydrogentransfer photoreaction in a crystalline solid: Acridine/fluoreneWe report a multifaceted investigation of the hydrogen transfer photoreaction in acridine-doped fluorene crystals at higher temperature. The purpose is to elucidate the role of vibrationally assisted tunneling in this reaction system. Raman experiments were conducted at various pressures and 77 K to document the change of vibrational frequency for the promoting mode͑s͒. Upon compression, a line with a large pressure coefficient emerges from under the strong phonon mode at 96.5 cm Ϫ1 . Through polarization studies under pressure, we have identified it as a molecular butterfly mode of B 1 symmetry. We have measured the reaction rate at 150 K in order to examine the effect of a suggested promoting mode at ϳ440 cm Ϫ1 . The reaction rate again increases exponentially with pressure, but with a significantly higher pressure coefficient than that at 1.4 and 77 K. Mode patterns based on a recently published ͓J. Phys. Chem. 98, 12 223 ͑1994͔͒ normal coordinate analysis of fluorene are used to help establish the promoting modes for this reaction. This consideration suggests that the 95 and 238 cm Ϫ1 modes are likely promoting modes in addition to the 125 cm Ϫ1 libration. A computation of the Franck-Condon factor for the H-transfer process indicates that a small population of a high overtone of a promoting mode may make a disproportionally large contribution to the reaction rate. This calculation fails to account for the greater pressure coefficient of the reaction rate at higher temperature. Instead, such an increase may come partly from a greater compressibility at higher temperature.

“…72. The ground electronic state values obtained from a normal mode analysis were assumed for calculating the present set of Coriolis coefficients; ti).…”

Section: Appendix C: Some Relevant Force and Other Coupling Constantsmentioning

confidence: 99%

Theory of anharmonically modified Coriolis coupling in the S1 state of benzene and relation to experiment

Helman

Marcus

1991

A voided crossings between quasidegenerate rovibrational states in the Doppler-free twophoton excitation of the 141 mode in the SI excited state of benzene are treated theoretically. Two sets of avoided crossings in plots of spectral line frequency vs J at a given K and !::J( have been reported experimentally between an initially prepared "light" state (14 1 in zeroth order) and dark states, namely, one which in zeroth orderis a 5 1 10 1 16 1 state, the other being in zeroth order a 6 2 111 and/or possibly a 3 1 16 1 state, implicated earlier by Neusser et al. The identification of these states makes the phenomenon an excellent candidate for treatment of the avoided crossing via a Van Vleck transformation, no other basis set states being needed for the diagonalization in order to extract the important features. Two successive transformations are used for handling direct coupling and coupling via virtual states. The dominant calculated contribution to the coupling is, jointly, Coriolis plus cubic--cubic anharmonic interactions between vibrational modes. Playing less of a role are Coriolis terms in which the inverse moment of inertia tensor is expanded up to quadratic terms in the coordinates. There results a 5 X 5 (for coupling to 5 1 10 1 16 1 ) and a 3 X 3 (for coupling to 6 2 111 or 3 1 16 1 ) matrix of the transformed Hamiltonian, each of which can also be described, if desired, to a very good approximation by a 2 X 2 matrix. The coupling element Vo and the difference of the rotational constants for the light and dark states (AB) are obtained from the plots of line position vs J(J + 1) obtained. For the 141 to 5 1 10 1 16 1 and for the 141 to 6 2 111 couplings the theoretical results are in reasonable agreement with the experimental results, no adjustable parameters being employed. For a coupling of 141 to 3 1 16 1 the calculated Vo would be much too high compared with experiment (a factor of 10), the coupling involving the exchange of only three instead off our vibrational quanta. A situation in which the 141 state is coupled to the 6 2 111 state to yield an avoided crossing and off-resonantly coupled to the 3 1 16 1 state would be consistent with some experimental results and not affect the reasonable agreement of the slope difference and splitting for the avoided crossing plots. 872 J. Chem. Phys. 95 (2), 15