We propose an alternative to the usual time–independent Born–Oppenheimer approximation that is specifically designed to describe molecules with Hydrogen bonds. In our approach, the masses of the Hydrogen nuclei are scaled differently from those of the heavier nuclei, and we employ a specialized form for the electron energy level surface. Consequently, anhar-monic effects play a role in the lead...

Low-lying collective excitations in even-even vibrational and transitional nuclei may be described semiclassically as quadrupole running waves on the surface of the nucleus ("tidal waves"), and the observed vibrational-rotational behavior can be thought of as resulting from a rotating condensate of interacting d bosons. These concepts have been investigated by measuring lifetimes of the levels ...

The present symposium brings together research in a number of fields: the quantum-chemical calculation of molecular potential-energy surfaces, rotational-vibrational spectroscopy, methods of calculating rotational-vibrational energy levels, unimolecular reactions and intramolecular dynamics. Several aspects of the work are discussed, including some recent developments on rates and products' qua...

The major factor determining the accuracy of ro-vibrational spectra of the water molecule is the accuracy of the Ž . underlying potential energy surface PES . We discuss improving the ab initio PES by introducing a correction to represent, accurately, the change in potential from equilibrium to linear geometries. We show the improvements which this has on calculated vibrational band origins and...

Vibrational autoionization of individual rotational levels of np (n ­ 1) and nf (n ­ 1) Rydberg states of nitric oxide (NO) with 11 # n # 15 have been studied employing two-color double-resonance excitation via the NO A S1 (ni ­ 1) state. The rotational state distributions of the resulting NO X S1 (n ­ 0) ion have been determined by time-of-flight photoelectron spectroscopy. These measurements ...

Understanding the detailed mechanism of protein folding requires dynamic, site-specific stereochemical information. The short time response of vibrational spectroscopies allows evaluation of the distribution of populations in rapid equilibrium as the peptide unfolds. Spectral shifts associated with isotopic labels along with local stereochemical sensitivity of vibrational circular dichroism (VC...

Spectral comparison is an important part of the assignment of the absolute configuration (AC) by vibrational circular dichroism (VCD), or equally by Raman optical activity (ROA). In order to avoid bias caused by personal interpretation, numerical methods have been developed to compare measured and calculated spectra. Using a neighbourhood similarity measure, the agreement between a computed and...

The backbone conformation of amphiphilic oligo(azobenzene) foldamers is investigated using vibrational circular dichroism (VCD) spectroscopy on a mode involving the stretching of the N=N bonds in the backbone. From denaturation experiments, we find that the VCD response in the helical conformation arises mainly from through-space interaction between the N=N-stretch transition-dipole moments, so...

2014 Radiative lifetime for 17 vibrational levels corresponding to 7 singlet and 3 triplet electronic states have been measured by using a delayed-coincidence method. We report first measurements of four H2 levels of which lifetimes range from 34 to 110 ns. J. Phys. France 49 (1988) 445-449 MARS 1988, Classification Physics Abstracts 34.80G

A breakdown of the standard Watson-type rotational Hamiltonian was suggested for a molecule with H2XYZ structure [Š. Urban and K. M. T. Yamada, J. Mol. Spectrosc. 160, 279–288 (1993)] . This breakdown is due to a near-resonant interaction between the ground state rotational levels and rotational levels in an excited vibrational state. This interaction has been observed in the excited electronic...