Details

Autor(en) / Beteiligte

• Hansen, Anne S.
• Huchmala, Rachel M.
• Vogt, Emil
• Boyer, Mark A.
• Bhagde, Trisha
• Vansco, Michael F.
• Jensen, Casper V.
• Kjærsgaard, Alexander
• Kjaergaard, Henrik G.
• McCoy, Anne B.
• Lester, Marsha I.

Titel

Coupling of torsion and OH-stretching in tert-butyl hydroperoxide. I. The cold and warm first OH-stretching overtone spectrum

Ist Teil von

• The Journal of chemical physics, 2021-04, Vol.154 (16), p.164306-164306

Ort / Verlag

United States: American Institute of Physics

Erscheinungsjahr

2021

Quelle

American Institute of Physics

Beschreibungen/Notizen

• 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. The jet-cooled spectrum is recorded by IR multiphoton excitation with UV laser-induced fluorescence detection of OH radical products, while direct IR absorption is utilized under thermal conditions. Prior spectroscopic studies of TBHP and other hydroperoxides have shown that the OH-stretch and XOOH (X = H or C) torsion vibrations are strongly coupled, resulting in a double well potential associated with the torsional motion about the OO bond that is different for each of the OH-stretching vibrational states. A low barrier between the wells on the torsional potential results in tunneling split energy levels, which leads to four distinct transitions associated with excitation of the coupled OH-stretch-torsion states. In order to interpret the experimental results, two theoretical models are used that include the OH-stretch-torsion coupling in TBHP. Both methods are utilized to compute the vibrational transitions associated with the coupled OH-stretch-torsion states of TBHP, revealing the underlying transitions that compose the experimentally observed features. A comparison between theory and experiment illustrates the necessity for treatments that include OH-stretch and COOH torsion in order to unravel the spectral features observed in the first OH-stretching overtone region of TBHP.