Temperature dependence of the IR driven cis-trans isomerization of nitrous acid (HONO)

Abstract

Temperature dependence of the IR driven cis-trans isomerization of nitrous acid (HONO)Botan, V; Hamm, P Hamm, P (2008). Temperature dependence of the IR driven cis-trans isomerization of nitrous acid (HONO) AbstractWith the help of ultrafast time-resolved infrared spectroscopy, we investigate the temperature dependence of the IR driven cis->trans isomerization of nitrous acid (HONO) in solid Kr. We find that the lifetime of the OH-stretch vibration, as well as the final cooling into the matrix, is affected only minimally (if at all) by temperature. Nevertheless, the quantum yield of the cis-> trans isomerization reaction increases by approximate to 30% to a total of 50%-70% when lowering the temperature from 30 to 15 K, whereas the trans->cis back yield is reduced by approximate to 40%. The results are discussed in analogy to Marcus theory of nonadiabatic electron transfer for the essentially barrierless case. We present a unified view of this important prototype proton transfer reaction that can explain the high cis->trans quantum yield of close to one. With the help of ultrafast time-resolved infrared spectroscopy, we investigate the temperature dependence of the IR driven cis → trans isomerization of nitrous acid ͑HONO͒ in solid Kr. We find that the lifetime of the OH-stretch vibration, as well as the final cooling into the matrix, is affected only minimally ͑if at all͒ by temperature. Nevertheless, the quantum yield of the cis → trans isomerization reaction increases by Ϸ30% to a total of 50%-70% when lowering the temperature from 30 to 15 K, whereas the trans → cis back yield is reduced by Ϸ40%. The results are discussed in analogy to Marcus theory of nonadiabatic electron transfer for the essentially barrierless case. We present a unified view of this important prototype proton transfer reaction that can explain the high cis → trans quantum yield of close to 1. Temperature dependence of the IR driven cis-trans isomerization of nitrous acid "HONO…

Formation and relaxation dynamics of iso-CH2Cl–I in cryogenic matrices

“…Our work has precedents in ultrafast studies of both isomerization and photolysis in cryogenic matrices. Hamm and coworkers have studied the infrared-driven, matrix-assisted isomerization of nitrous acid (HONO) in rare-gas matrices on the fs to μs time scale, [20][21][22][23] and Apkarian and co-workers [24][25][26][27][28] and Schwentner and co-workers [29][30][31][32] have performed extensive analyses of ultraviolet photolysis of halogen molecules in rare-gas matrices. These results are notable in showing that strong interactions with the solvent cage mediate the transfer of energy between the chromophore and solvent.…”

Effect of the overall rotation on the cis–trans isomerization of HONO induced by an external field

“…Consequently, since HONO is a molecule of high environmental and fundamental interest, it has spurred numerous experimental and theoretical works. [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] In a previous paper on HONO, 20 we have triggered the cistrans isomerization via a laser field. We have simulated the dynamics with MCTDH in the presence of a laser pulse with a carrier frequency of 850 cm À1 , a field strength of 0.0035 a.u.…”

Ultrafast Time-Resolved Vibrational Spectroscopy at University of Zurich

“…HONO, [29][30][31] which features an exceptionally high isomerization quantum yield of close to 100%. This high quantum could be explained through a funnel-like energy pathway.…”

“…This high quantum could be explained through a funnel-like energy pathway. [31] Vibrational Polarons…”