Vincent A. Venturo

Raman‐vibronic double‐resonance spectroscopy of benzene dimer isotopomers

1. B.F. Henson, G.V. Hartland, V.A. Venturo, R.A. Hertz, and P.M. Felker, Chem. Phys. Lett.176,91 (1991). 2. B.F. Henson, G.V. Hartland, V.A. Venturo, and P.M. Felker -- to be submitted.

Intermolecular Raman bands in the ground state of benzene dimer

Mass‐selective, ionization‐detected stimulated Raman spectroscopies have been applied to a study of low‐frequency structure in the ground states of benzene dimer isotopomers. The results reveal two Raman bands below 10 cm−1, as well as structure in the range of 47 to 53 cm−1. Tentative assignments for the bands are proposed.

The Raman and vibronic activity of intermolecular vibrations in aromatic‐containing complexes and clusters

Theoretical and experimental results pertaining to the excitation of intermolecular vibrations in the Raman and vibronic spectra of aromatic‐containing, weakly bound complexes and clusters are reported. The theoretical analysis of intermolecular Raman activity is based on the assumption that the polarizability tensor of a weakly bound species is given by the sum of the polarizability tensors of its constituent monomers. The analysis shows that the van der Waals bending fundamentals in aromatic–rare gas complexes may be expected to be strongly Raman active. More generally, it predicts strong Raman activity for intermolecular vibrations that involve the libration or internal rotation of monomer moieties having appreciable permanent polarizability anisotropies. The vibronic activity of intermolecular vibrations in aromatic‐rare gas complexes is analyzed under the assumption that every vibronic band gains its strength from an aromatic‐localized transition. It is found that intermolecular vibrational excitatio...

Raman/vibronic double-resonance spectroscopy of benzene-doped argon clusters

Abstract Results of mass-selective, ionization-loss stimulated Raman spectroscopy on benzene-(Ar)n, n = 1–22, clusters are reported. The results prove the existence of at least two different gross cluster types in the size range from n = 16–20. The evidence suggests that these cluster types are distinguished from one another by the number of Ar atoms bound in the plane of the benzene moiety.

Mass‐selective ionization‐detected stimulated Raman spectroscopy of benzene trimer and higher clusters

We present the results of mass‐selective, ionization‐detected stimulated Raman spectroscopies on jet‐cooled benzene clusters from the trimer to the octamer. The data pertain to the fundamentals of the totally symmetric ring‐breathing (ν1) and C–H stretch (ν2) modes of benzene and provide information about geometrical structure and vibrational dynamics. For the trimer, the results indicate a species in which all three benzenes reside in equivalent sites. For the higher clusters the results point to geometries involving two or more inequivalent sites. The ν1‐excited trimer is found to decay on a nanosecond, or longer, time scale. The ν2‐excited trimer decays on a time scale of greater than 5 ps. Similar timescales characterize the decays of the ν2‐excited tetramer and pentamer.

The geometry of carbazole-(Ar)2 from rotational coherence spectroscopy

Abstract Rotational coherence spectroscopy has been used to investigate the geometry of the carbazole—(Ar) 2 cluster. The data strongly indicate that the structure has one argon atom above and the other below the central ring of the carbazole moiety. This result is contrary to the minimum-energy structure predicted by calculations based on a widely used intermolecular potential energy function. Possible reasons for this discrepancy are discussed.

Size‐selective Raman spectroscopy of carbazole–(Ar)n clusters at sub‐wave‐number resolution

Size‐selective Raman spectra of carbazole–(Ar)n clusters (n=0–14) obtained between about 1305 and 1325 cm−1 by mass‐selective ionization‐loss stimulated Raman spectroscopy are reported. The spectra are interpreted with respect to vibrational energy flow and argon evaporation, and are compared with vibronic spectroscopic results on the species.

Stimulated Raman spectroscopy of complexes and clusters in supersonic molecular beams

Mass-selective, ionization-detected stimulated Raman spectroscopies and their advantages in the size-selective vibrational spectroscopy of clusters in supersonic molecular beams are described. Results from the application of such methods to benzene dimer, phenol-water, and carbazo1e-(Ar)n clusters are presented and discussed.