| Autor: |
Castillo-Chara, J., McIntosh, A. L., Wang, Z., Lucchese, R. R., Bevan, J. W. |
| Předmět: |
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| Zdroj: |
Journal of Chemical Physics; 6/8/2004, Vol. 120 Issue 22, p10426-10441, 16p, 3 Diagrams, 13 Charts, 4 Graphs |
| Abstrakt: |
Supersonic jet investigations of the (HBr)2 dimer have been carried out using a tunable diode laser spectrometer to provide accurate data for comparison with results from a four-dimensional (4-D) ab initio potential energy surface (PES). The near-infrared v1 ±, v2 ±, and ( v1 + v4)- bands of (H 79Br)2 , (H 79Br—H 81Br), and (H 81Br)2 isotopomers have been recorded in the range 2500–2600 cm-1 using a CW slit jet expansion with an upgraded near-infrared diode laser spectrometer. The 4-D PES has been calculated for (HBr)2 using second-order Møller—Plesset perturbation theory with an augmented and polarized 6-311G basis set. The potential is characterized by a global minimum occurring at the H bond structure with the distance between the center of masses (CM) of the monomer being RCM = 4.10 Å with angles θA = 10°, θB = 100° and a well depth of 692.2 cm-1, θA is the angle the HBr bond of monomer A makes with the vector from the CM of A to the CM of B, and θB is the corresponding angle monomer B makes with the same CM—CM vector. The barrier for the H interchange occurs at the closed C2h structure for which RCM = 4.07 Å, θA = 45°, θB = 135°, and the barrier height is 73.9 cm-1. The PES was fitted using a linear-least squares method and the rovibrational energy levels of the complex were calculated by a split pseudospectral method. The spectroscopic data provide accurate molecular parameters for the dimer that are then compared with the results predicted on the basis of the 4-D ab initio PES. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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