Matrix isolation investigation of the vibrational spectroscopy and photochemistry of complexes of HCl and HBr with nitric oxide. ab initio study of the NO:HCl complex structure

Abstract

The matrix isolation technique has been used to isolate and characterize the complexes two hydrogen halides (HCl and HBr) and the nitric oxide (monomer and cis dimer). Identification of the complexes was performed through the observation of the HX and (NO) x (x=1,2) submolecule stretching modes. Ab initio calculation shows that the most stable structure ClH:NO is linear with a 0.002 Å shortening of the NO bond distance and an increase of the HCl bond length with an identical amount. Photochemistry of the identified complexes was also studied. The photoproduct of both NO:HX and (NO) 2 HX complexes is XNO (X=Cl, Br) upon UV irradiation. In the case of the (NO) 2:HX complex the XNO molecule is complexed to HNO in the matrix cage.