Photodissociation Dynamics of Cumene Hydroperoxide at 248 and 193 nm

Abstract

Photodissociation dynamics of cumene hydroperoxide at 248 and 193 nm producing (C 6 H 5 )(CH 3 ) 2 CO (CumO) and OH fragments has been investigated by measuring laser induced fluorescence spectra of the OH fragments, which are produced exclusively in the ground electronic state. The measured energy distributions among the fragments are f r (OH) ) 0.03, f t ) 0.49, f int (CumO) ) 0.48 and f r (OH) ) 0.03, f t ) 0.18, f int (CumO) ) 0.79 at 248 and 193 nm, respectively, and negligible vibrational excitation in OH was observed at both wavelengths. At 248 nm, slightly negative µ-V and positive V-J vector correlations were observed by analyzing the Doppler profiles of the rotationally resolved OH spectra, whereas no vector correlations were observed at 193 nm. From the measurements, detailed photodissociation dynamics of cumene hydroperoxide is discussed compared to the case of tert-butyl hydroperoxide previously studied.

Thermolysis and photolysis of 2-ethyl-4-nitro-1(2H)-isoquinolinium hydroperoxide

“…One obvious observation that can be made from DD plots is that most of the charge redistribution involves the isoquinoline framework, while the O – O moiety exhibits only minor changes in the electron density redistribution upon excitation. The photolysis of peroxides usually occurs via n → σ * transition, and this type of excited state should give rise to DD plots with large excited‐state redistribution of electronic charge around the O – O group. On the contrary, the S 1 → S 0 DD plot of IQOOH exhibits essentially π → π * character with a certain degree of charge‐transfer from the donating phenyl group to accepting nitro group.…”

Vibrational spectroscopy and dissociation dynamics of cyclohexyl hydroperoxide

“…This is in stark contrast to near UV photodissociation studies of H 2 O 2 and organic hydroperoxides, which predominantly yield rovibrationally cold OH products. [43][44][45][46][47][48] Studies have been extended to tert-butyl hydroperoxide (TBHP), where a sequence of OH-stretch transitions from the fundamental through the h overtone has been characterized. 40,41 Recent work revealed a strong feature at ∼7017 cm −1 arising from the rst overtone OH stretch (2n OH ), which is heavily coupled to COOH torsion.…”

“…This is in stark contrast to near UV photodissociation studies of H 2 O 2 and organic hydroperoxides, which predominantly yield rovibrationally cold OH products. 43–48…”