Highly vibrationally excited HCN/HNC: Eigenvalues, wave functions, and stimulated emission pumping spectra

Abstract

Articles you may be interested inAb initio calculation of a global potential, vibrational energies, and wave functions for HCN/HNC, and a simulation of the A-X̃ emission spectrum J. Chem. Phys. 99, 308 (1993); 10.1063/1.465809 Highly excited vibration-rotation states of floppy triatomic molecules by a localized representation method: The HCN/HNC molecule J. Chem. Phys. 93, 3039 (1990); 10.1063/1.458838 The extraction of dynamics and the classical mechanical simulation of low resolution regular and chaotic spectra: HCN/HNC J. Chem. Phys. 93, 76 (1990); 10.1063/1.459529 The vibrational spectrum and the isomerization potential of HCN/HNC J. Chem. Phys. 92, 3633 (1990); 10.1063/1.457819 Accurate localized and delocalized vibrational states of HCN/HNCWe report the large scale calculation of accurate vibrational eigenstates of X state HCN/ HNC up to -37 000 cm-t . The discrete variable representation-distributed Gaussian basis (DVR-DGB) approach is used. In the final major computational step, large dense Hamiltonian matrices (> 11 000 rows or columns) must be diagonalized. The use of new software for out-of-core eigenproblems is described in some detail. Representative wave functions of high lying vibrational eigenstates near the isomerization barrier and at energies up to 39 313 cm -I_are presented. Theoretical stimulated emission pumping (SEP) spectra for several initial (A) vibrational states are presented along with calculations of the quantum survival probability for these spectra. The spectra range from being dominated by localized eigenstates to being dominated by delocalized eigenstates, depending on the geometry .of each initial state. In addition, time-dependent expectation values of the coordinates of the evolving wave packet are plotted.

THEORETICAL STUDIES OF $\tilde{A}{}^1 A^{\prime\prime}\to\tilde{X}{}^1 A^\prime$ RESONANCE EMISSION SPECTRA OF HCN/DCN USING SINGLE LANCZOS PROPAGATION METHOD

“…2,[22][23][24][25][26][27] There are two major ingredients in a quantum investigation of highly excited vibrational dynamics, namely an accurate global PES and efficient solution of the vibrational eigenequation. Much effort has been devoted in this case to the development a global PES that is capable of describing both isomers as well as the isomerization barrier.…”

“…2,24,[39][40][41][42] However, all previous studies were based on empirical PESs of some form for theà 1 A state and imposed the Condon approximation that assumes a constant transition dipole. These approximations lead to uncertainties that are not readily interpretable.…”

Stimulated emission pumping spectroscopy of HCP near the isomerization barrier: EVIB≤25 315 cm−1

“…On the other hand, Bentley et al carried out an ab initio calculation on the spectrum of highly vibrationally excited HCN/HNC. 2 They calculated eigenvalues, wave functions, and theoretical SEP spectra. Their calculation showed that the wave functions of levels which are located near or above the isomerization barrier, such as ͑0,4,4͒ or ͑5,10,0͒, are localized in the HCN well.…”

Dynamics Study of the Reaction Ar + HCN → Ar + H + CN

“…However, they have considered only stabilized metastable HO 2 molecules and a constant density of states and hence avoided the unimolecular dissociation as well as the definition of the density of states. Accurate calculations of the rovibrational levels of HCN have been reported by several authors [39][40][41] using variational methods and different potential energy surfaces. Unfortunately, these calculations have been carried out only for low total angular momenta (J e 2) and energies up to ca.…”