15min:
OBSERVATION OF A PLANAR ISOMER OF THE N2O-(C2H2)2 TRIMER.

S. SHEYBANI-DELOUI, J. NOROOZ OLIAEE, M. REZAEI, N. MOAZZEN-AHMADI, Department of Physics and Astronomy, University of Calgary, 2500 University Drive North West, Calgary, Alberta, Canada T2N 1N4; A. R. W. MCKELLAR, National Research Council of Canada, Ottawa, Ontario, Canada K1A 0R6.

Infrared spectra of a planar isomer of the N2O-(C2H2)2 are observed in the region of nu1 fundamental band of N2O monomer ( sim2224~cm-1) using a quantum cascade laser to probe a pulsed supersonic slit jet expansion. The band is simulated by an asymmetric top Hamiltonian with rotational constants of A=2871 MHz, B=1140 MHz, C=816 MHz and hybrid a/b-type transitions. It shows a relatively large blue-shift of about 9 cm-1 with respect to the N2O monomer band origin. In addition to the normal istopologue, 15N2O-(C2H2)2 and N2O-(C2D2)2 are also observed. Here, we present our observation and experimental results which agree fairly well with a semi-empirical calculation which indicates that the lowest energy isomer has a planar structure very similar to that of OCS-(C2H2)2.