Photolysis of o-Nitrobenzaldehyde in the Gas Phase: A New OH. Formation Channel

✍ Scribed by Shi-Bo Cheng; Can-Hua Zhou; Hong-Ming Yin; Ju-Long Sun; Ke-Li Han

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 405 KB
• Volume: 10
• Category: Article
• ISSN: 1439-4235
• DOI: 10.1002/cphc.200800735

✦ Synopsis

Abstract

New route to gas‐phase OH^.^: UV photolysis of gaseous o‐nitrobenzaldehyde forms OH radicals via the transformation into the ketene or __o‐__nitrosobenzoic acid intermediate (see figure). The OH^.^ product is monitored by single‐photon laser‐induced fluorescence (LIF).magnified image

Photolysis of gaseous o__‐nitrobenzaldehyde (o‐NBA) with selected different excitation wavelengths (355‐400 nm) is investigated, and the nascent OH radical is detected by the single‐photon laser‐induced fluorescence (LIF) technique. The relative quantum yield and rotational excitation of OH formation are found to be dependent on the excitation energy. The distributions of rotational, spin–orbit, and Λ‐doublet states are obtained at 355–400 nm by analyzing the experimental data. The OH radicals are found to be vibrationally cold at all photolysis wavelengths. The spin–orbit and Λ‐doublet states have nonstatistical distributions. To understand the dissociative process involved in the OH‐generating channel, DFT calculations are performed. Based on both experimental and theoretical results, possible photolysis channels of__ o__‐NBA leading to the OH fragment are proposed and discussed.__