HY•••N2 and HXeY•••N2 complexes in solid xenon, (Y=Cl and Br): Unexpected suppression of the complex formation for deposition at higher temperature

The 1:1 complexes of HY and HXeY (Y=Cl and Br) with nitrogen are characterized by FTIR spectroscopy in a Xe matrix. These complexes show small blue shifts of the HY and H-Xe stretching frequencies with respect to the monomers (ca. + 10 cm(-1)). In the HXeY center dot center dot center dot N-2 synthesis procedure, a HY/N-2/Xe matrix with HY center dot center dot center dot N-2 complexes is first photolyzed at 193 nm to yield isolated H and Y center dot center dot center dot N-2 fragments. At the second step, annealing at ca. 40 K activates mobility of H atoms and promotes the H+Xe+Y center dot center dot center dot N-2 reaction. It is quite remarkable that the HY center dot center dot center dot N-2 and consequently HXeY center dot center dot center dot N-2 complexes are observed in Xe matrices deposited at relatively low temperature (below ca. 35 K). For Xe matrices deposited above ca. 40 K, HY molecules do not form a complex with nitrogen and the HXeY center dot center dot center dot N-2 complex does not appear after photolysis and annealing; however, this observation is not explained in this article. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3472976]