Fine effects of the hydration, charge, and conformational structural changes in L-alanyl-L-alanine (Ala-Ala) dipeptide were studied with the aid of Raman and Raman optical activity (ROA) spectra. The spectra were recorded experimentally and analyzed by means of density functional computations. A (15)N and (13)C isotopically labeled analogue was synthesized and used to verify the vibrational mod...

Restricted Hartree–Fock 6-31G calculations of electrical and mechanical anharmonicity contributions to the longitudinal vibrational second hyperpolarizability have been carried out for eight homologous series of conjugated oligomers—polyacetylene, polyyne, polydiacetylene, polybutatriene, polycumulene, polysilane, polymethineimine, and polypyrrole. To draw conclusions about the limiting infinit...

We analyze the nonstationary vibrational states prepared by ultrashort laser pulses interacting with a two electronic level molecular system. Fully quantum mechanical expressions are derived for all the moments of the coordinate and momentum operators for the vibrational density matrices associated with the ground and excited electronic states. The analysis presented here provides key informati...

The vibrational properties of single-walled carbon nanotubes reflect the electron and phonon confinement as well as the cylindrical geometry of the tubes. Raman scattering is one of the prime techniques for studying the fundamental properties of carbon tubes and nanotube characterization. The most important phonon for sample characterization is the radial-breathing mode, an in-phase radial move...

Self-trapping of NH-stretch vibrational excitations in synthetic beta-sheet helices is observed using femtosecond infrared pump-probe spectroscopy. In a dialanine-based beta-sheet helix, the transient-absorption change upon exciting the NH-stretch mode exhibits a negative absorption change at the fundamental frequency and two positive peaks at lower frequencies. These two induced-absorption pea...

[1] We report the high-pressure thermoelastic and vibrational thermodynamic parameters for hexagonal close-packed iron (e-Fe), based on nuclear resonant inelastic X-ray scattering and in situ X-ray diffraction experiments at 300K. Long data collection times, high-energy resolution, and quasi-hydrostatic sample conditions produced a high-statistical quality data set that comprises the volume-dep...

Using the laser photoelectron attachment (LPA) method at an energy width of 1–2 meV, the Br− yield due to dissociative electron attachment to the molecule CH3Br has been measured over the energy range 1–180 meV at a gas temperature of 600 K. The data clearly exhibit the vibrational Feshbach resonance predicted by Wilde et al. (2000 J. Phys. B: At. Mol. Opt. Phys. 33 5479) and associated with th...