Journal ArticleDOI
Vibrational structure of hydrogen cyanide up to 18 900 cm −1
TLDR
In this article, a set of anharmonic vibrational constants was derived, unifying the SEP data reported here with previous infrared and overtone data, which is expected to be able to predict the position of normal mode states below 19 000 cm−1 with an accuracy within 3 cm −1.Abstract:
Stimulated-emission pumping (SEP) spectra of HCN have been measured by using a pulsed, tunable argon fluoride laser with a frequency-doubled, pulsed dye laser. Sixty-seven vibrational states of the ground electronic state between 8 900 and 18 900 cm−1 have been observed. Eighty percent of the states can be described within a traditional normal mode context. A full set of anharmonic vibrational constants was derived, unifying the SEP data reported here with previous infrared and overtone data. This set of molecular constants is expected to be able to predict the position of normal mode states below 19 000 cm−1 with an accuracy within 3 cm−1. Twenty percent of the states could not be assigned to unperturbed normal mode states, and a systematic analysis was performed in an attempt to find a simple explanation for them based on possible perturbations. Except for the lowest energies, no simple explanation was found, suggesting that delocalized isomerizing vibrational states are playing a role in the observed vibrational structure at higher energy. Direct comparison with assigned normal mode states derived from quantum-mechanical vibrational-structure calculations on the only available three-dimensional potential energy surface were made possible by these experiments. The deviation between experiment and theory as a function of the number of bending quanta, the vibrational motion that couples strongly to the isomerization reaction coordinate, makes clear that the isomerization barrier height is too low on this surface. The present state of experimental characterization of the HCN system should be good enough to permit a high-quality potential energy surface to be derived for highly vibrationally excited HCN.read more
Citations
More filters
Journal ArticleDOI
Vibrational energy transfer
TL;DR: In this paper, the collision dynamics of vibrational energy transfer are discussed. But the main focus is on three broad areas within this field: (i) vibrational transfer in large molecules (>10 modes) at low excitation, (ii) vibration energy transfer of large molecules at high vibrational excitation and (iii) vibration transfer of highly excited small molecules.
Journal ArticleDOI
Ab initio calculation of a global potential, vibrational energies, and wave functions for HCN/HNC, and a simulation of the (A-tilde)-(X-tilde) emission spectrum
TL;DR: In this paper, the authors present a potential energy surface for the HCN/HNC system which is a fit to extensive, high quality ab initio, coupled-cluster calculations.
Journal ArticleDOI
HCP CPH ISOMERIZATION: Caught in the Act
Haruki Ishikawa,Robert W. Field,Stavros C. Farantos,Marc Joyeux,J. Koput,Christian Beck,Reinhard Schinke +6 more
TL;DR: The vibrational spectrum of phosphaethyne, HCP, in its electronic ground state, as revealed by complementary experimental and theoretical examinations is discussed, which provides a detailed spectroscopic picture of the breaking of one bond and the formation of a new one.
Journal ArticleDOI
THE DYNAMICS OF “STRETCHED MOLECULES”: Experimental Studies of Highly Vibrationally Excited Molecules With Stimulated Emission Pumping
TL;DR: In this article, a review of stimulated emission pumping as used to study molecular dynamics is presented, including unimolecular as well as scattering studies, including vibrational redistribution, van der Waals clusters, vibrational energy transfer, gas-surface interactions, atmospheric effects resulting from nonequilibrium vibrational excitation, and vibrational promotion of electron transfer.
Journal ArticleDOI
Perturbative calculations of vibrational (J=0) energy levels of linear molecules in normal coordinate representations
Anne B. McCoy,Edwin L. Sibert +1 more
TL;DR: In this article, the authors used Van Vleck perturbation theory to transform curvilinear and rectilinear normal coordinate vibrational Hamiltonians of HCN, C2H2, and CO2 to block-diagonal effective Hamiltonians.
References
More filters
Journal ArticleDOI
Discrete variable representations and sudden models in quantum scattering theory
TL;DR: In this article, an exact formalism in which the scattering problem may be described by sets of coupled equations labeled either by basis functions or quadrature points is presented, and the simply evaluated unitary transformation which connects them results in an efficient procedure for performing quantum scattering calculations.
Journal ArticleDOI
Stimulated Emission Pumping: New Methods in Spectroscopy and Molecular Dynamics
TL;DR: In this article, the authors deal with spectra far from the textbook limit of small amplitude motions and ask questions of these spectra that are not the traditional ones of equilibrium structure, and propose a new technique called Stimulated Emission Pumping (SEP) for studying an extraordinarily wide range of rotation-vibration levels in the ground electronic states or other low-lying electronic states of diatomic and small polyatomic molecules.
Journal ArticleDOI
Accurate localized and delocalized vibrational states of HCN/HNC
Zlatko Bačić,John C. Light +1 more
TL;DR: In this article, the first accurate quantum calculation of the delocalized, large amplitude motion vibrational (J=0) levels of HCN/HNC, lying above the isomerization barrier, is presented.
Journal ArticleDOI
Molecular beam studies of the F+D2 and F+HD reactions
Daniel M. Neumark,Alec M. Wodtke,Gary N. Robinson,Carl C. Hayden,Kosuke Shobatake,R. K. Sparks,T. P. Schafer,Yuan T. Lee +7 more
TL;DR: In this article, the F+D2 and F+HD reactions were investigated in a high-resolution crossed molecular beams experiment at several collision energies, and the DF product from both reactions was predominantly backward scattered although some forward scattered DF(v=4) was observed at the highest energy studied.
Journal ArticleDOI
Potential energy surface for the model unimolecular reaction HNC → HCN
TL;DR: In this article, extended basis sets were used in conjunction with both self-consistent−field (SCF) and configuration interaction (CI) wavefunctions to determine the more important features of the potential energy surface for the simple isomerization reaction HNC → HCN.