Photofragmentation of NOCl in a molecular beam at 193 nm: a bimodal vibrational state distribution

Resonance Raman spectroscopy in the dissociative A band of nitrosyl chloride

“…1 ͑The band was named before current naming conventions were established, and so the A band lies above the B, C, etc., bands in energy.͒ The A band is intense, with an absorption cross section of approximately 6.5 ϫ10 Ϫ17 cm 2 at its peak near 196 nm wavelength. It has been suggested that as many as three electronically excited states may participate in the absorption, [4][5][6] with the proportion from each state varying with wavelength within the band. It has been suggested that as many as three electronically excited states may participate in the absorption, [4][5][6] with the proportion from each state varying with wavelength within the band.…”

“…2,3 The breadth of the band ͓ϳ5000 cm Ϫ1 full width at half maximum ͑FWHM͔͒ and absence of structure indicate rapid and direct dissociation following excitation. 7,8 Despite a large number of studies of the photofragments, [4][5][6][9][10][11][12] a complete picture of the photodissociation is still elusive. This supposition is not unequivocally established, however, and runs counter to the prediction of ab initio calculations on ClNO.…”

Femtosecond Pump−Probe Studies of Nitrosyl Chloride Photochemistry in Solution

“…As mentioned in the Introduction, photochemical studies of gaseous ClNO employing wavelengths resonant with the A-band have shown that Cl and NO formation is the dominant photochemical pathway. 25,36,[39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] In contrast, the structural isomer (ClON) is the only photoproduct observed in low-temperature matrix studies. 63,64 The results presented here represent the first detailed measurements of ClNO photochemistry in solution.…”

“…38 The photochemistry of gaseous ClNO is dominated by formation of the photoproducts, NO ( 2 Π ( 1 / 2 , ( 3 / 2 ) and Cl ( 2 P 1/2,3/2 ), with near-unity quantum yield. 25,36,[39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] The absorption spectrum of ClNO consists of a series of bands referred to as the K through A bands as one proceeds from low to high energy. 57,58 The A-band dominates the absorption spectrum and has an absorption maximum of 196 nm in the gas phase.…”

“…23,40,41,50,51,53 A bimodal distribution of NO vibrational energy was observed, suggesting that dissociation is mediated by two or more electronic excited states. 50,53 The production of the Cl ( 2 P 3/2 ) and Cl* ( 2 P 1/2 ) following ClNO photolysis has also been interpreted in terms of multiple excited states residing within the A-band. 52,54,55 This hypothesis is supported by theoretical studies of ClNO.…”