Matrix isolation Fourier transform infrared study of photodecomposition of formimidic acid.
The UV isomerization of formamide (HCONH2) trapped in xenon, nitrogen, argon, and neon cryogenic matrices has been monitored by Fourier transform infrared (FT-IR) spectroscopy. Formamide monomer is the only species present in the matrices after deposition; when UV-selective irradiation was carried out at 240 nm, the n --> pi transition allowed us to observe the formation of several isomers of formimidic acid [H(OH)C=NH]. On these latter species, we carried out selective IR irradiation of their OH stretching mode and compared the experimental and theoretical (B3LYP/6-311+G(2d,2p)) sets of bands. This study allowed us to characterize for the first time all the isomers of formimidic acid. We have then studied the vacuum UV photodecomposition (lambda > 160 nm) of this molecule at 10 K in argon and xenon matrices. Several primary photoproducts such as HCN.H2O, HNC.H2O, and HNCO.H2 complexes, yielded by dehydration and dehydrogenation processes, were characterized.
Duvernay
Fabrice
F
Physique des Interactions Ioniques et Moléculaires, Unité mixte de recherche 6633, Université de Provence et Centre National de la Recherche Scientifique, Centre de St Jérôme, case 252, 13397 Marseille Cedex 20, France.
Trivella
Aurelien
A
Borget
Fabien
F
Coussan
Stephane
S
Aycard
Jean-Pierre
JP
Chiavassa
Thierry
T