Rovibrational analysis of the nu(2) band of diazirine-d(2)

The gas-phase IR spectrum of the v(2) (A(1), 1610.33 cm(-1)) band of the de uterated isotopomer of diazirine. D2CN2, a three-membered ring compound whi ch belongs to the molecular symmetry point group CZ,, has been studied at a resolution of about 0.005 cm(-1). This vibrational mode which can be appro ximately described as N=N stretching is widely perturbed. This is due to va rious interactions with the tetrad consisting of the binary combinations v( 0) + v(7) (A(1)), v(7) + v(9) (A(2)), v(5) + v(6) (B-2). and v(5) + v(9) (B -1). which form a relatively isolated pentad together with v(2) in the wave number region 1560-1610 cm(-1). A simultaneous upper state analysis of v(2) from a pentad model including these resonances has been performed and a se t of spectroscopic parameters has been obtained. Since the four combination bands of the pentad are dark states, only band centers could be determined : in addition for v(5) + v(9) and v(7) + vs also the term (B - C)/2 has bee n obtained. A number of Coriolis interaction constants and the vibrational resonance (with v(6) + v(7)) parameter have been calculated as well. (C) 20 01 Academic Press.