Spectroscopy and structures of free radicals and molecular ions

Spectroscopic and Kinetic Studies of the ClSO Radical from Cl2SO Photolysis

“…While we were not certain about the identity of the origin of spectrum, we found that it is not similar to possible side products (e.g., Cl 2 , NO 2 , N 2 O 5 ), and so we speculate this could be due to the adduct of ClSO and NO 2 (Figures S10–S12). Besides, the far-infrared and rotational spectra were assigned to the ClSO radicals based on several chemical tests, including formation from the Cl + SO reaction. , It seems that SO and ClSO have the potential to be the Cl atom reservoirs by forming Cl 2 SO, which was not mentioned in Venus’ atmospheric models. , Furthermore, the ClSO radicals may be a general radical reservoir through recombination reactions under high pressure, which is worth further studying. This work also suggested that the Cl atom yield from Cl 2 SO photolysis in the solution phase or solid phase could be even smaller than in the gas phase due to the cage effect and the high energy transfer efficiency to the environment due to the rapid Cl + ClSO → Cl 2 SO reaction.…”

“…Besides, the far-infrared and rotational spectra were assigned to the ClSO radicals based on several chemical tests, including formation from the Cl + SO reaction. 28,29 It seems that SO and ClSO have the potential to be the Cl atom reservoirs by forming Cl 2 SO, which was not mentioned in Venus' atmospheric models. 61,62 Furthermore, the ClSO radicals may be a general radical reservoir through recombination reactions under high pressure, which is worth further studying.…”

“…In the gas phase, the far-IR spectrum has been reported, but no analysis was done . The microwave spectrum was mentioned in the literature without available data . Chu et al have measured the IR spectrum of the nascent products from Cl 2 SO photolysis at 248 nm, and the ClSO radicals were identified by matching the simulation of the rotational resolved SO stretching band to experimental observations .…”

“…28 The microwave spectrum was mentioned in the literature without available data. 29 Chu et al 30 have measured the IR spectrum of the nascent products from Cl 2 SO photolysis at 248 nm, and the ClSO radicals were identified by matching the simulation of the rotational resolved SO stretching band to experimental observations. 30 Only one kinetic measurement of the ClSO radical has been performed; using mass spectroscopy, 31 Blitz et al reported a ClSO + NO 2 reaction rate coefficient of (8.0 ± 1.2) × 10 −12 cm 3 molecule −1 s −1 at 1 Torr He, but no products were found in the mass spectrum.…”

Structural and Chemical Properties of Silyl Radicals

“…The electron affinity (EA),13 ionization potential (IP),14 and heat of formation (AHVjs)15 were all measured directly, while most of the molecular constants such as the inversion barrier and the angle a(H-Si-H) have been extracted from experimental modeling data. The H3Si' radical is bent out of the plane by 16.0 ± 2.0°( angle y in 1) corresponding to an a angle of 112.5 ± 2.0°. 13 The inversion barrier in H3Si' is 5.4 kcal mol-1.13 '16 The EAs of a variety of silyl radicals have been measured by means of electron photodetachment experiments (Table 1), in which the anion population was monitored as a function of the wavelength of irradiating light (eq l).17 '18 The EAs reported in R3Si" -R3Si' + e~ (1) Table 1 indicate that (i) replacement of a hydrogen by a methyl group decreases the EA, the effect being cumulative, (ii) substitution of a phenyl for hydrogen has essentially no effect on the EA, and (iii) replacement of a hydrogen by an Me3Si group increases the EA, the effect being cumulative.…”