The infrared (IR) spectrum of tert-butyl hydroperoxide (TBHP) in the region of the first OH-stretching overtone has been observed under jet-cooled and thermal (300 K, 3 Torr) conditions at ∼7017 cm−1. of Washington, Seattle, WA (United States) Sponsoring Org.: USDOE Office of Science (SC), Basic Energy Sciences (BES) Independent Research Fund Denmark National Science Foundation (NSF) Carlsberg Foundation OSTI Identifier: 1853713 Alternate Identifier(s): OSTI ID: 1780495 Grant/Contract Number: SC0021081 9040-00142B OAC-1663636 CHE-1624430 CHE-1955068 CF18-0614 9036-00016B FA187181/A154987 Resource Type: Accepted Manuscript Journal Name: Journal of Chemical Physics Additional Journal Information: Journal Volume: 154 Journal Issue: 16 Journal ID: ISSN 0021-9606 Publisher: American Institute of Physics (AIP) Country of Publication: United States Language: English Subject: 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY vibrational spectra gas phase quantum mechanical calculations potential energy surfaces transition moment Fourier transform spectroscopy torsional dynamics Franck Condon = , University of Pennsylvania, Philadelphia, PA (United States).University of Washington, Seattle, WA (United States).The accuracy of the Franck–Condon treatment of these features improves with increasing Δv OH. We also explore the torsional dependence of the OH-stretching transition dipole moment and show that a Franck–Condon treatment fails to capture the intensity in the region of the stretch–torsion combination features. We have developed two complementary vibrational models to describe the spectra of the OH-stretching regions, a reaction path model and a reduced dimensional local mode model, both of which describe the features of the vibrational spectra well. In each of the OH-stretching regions, both an OH-stretching and a stretch–torsion combination feature are observed, and we show direct evidence for the tunneling splitting in the OH-stretching fundamental region. The double-well nature of the COOH torsion potential leads to tunneling splitting of the energy levels and, combined with the low frequency of the torsional vibration, results in spectra in the OH-stretching regions with multiple vibrational transitions. In hydroperoxides, the OH-stretching and COOH torsion vibrations are strongly coupled.
We report the vibrational spectra of gas phase tert-butyl hydroperoxide have been recorded in the OH-stretching fundamental and overtone regions (Δv OH = 1–5) at room temperature using conventional Fourier transform infrared (Δv OH = 1–3) and cavity ring-down (Δv OH = 4–5) spectroscopy.
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