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...N(2) synthesis procedure, a HY/N(2)/Xe matrix with HY...N(2) complexes is first photolyzed at 193 nm to yield isolated H and Y...N(2) fragments. At the second step, annealing at ca. 40 K activates mobility of H atoms and promotes the H+Xe+Y...N(2) reaction. It is quite remarkable that the HY...N(2) and consequently HXeY...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...N(2) complex does not appear after photolysis and annealing; however, this observation is not explained in this article.