Fourier transform emission spectroscopy and ab initio calculations on OsN

摘要

The emission spectrum of OsN has been recorded in the 3000-13 000 cm~(-1) region using a Fourier transform spectrometer. OsN molecules were excited in an osmium hollow cathode lamp operated with neon gas and a trace of nitrogen. Six bands observed in the 8000-12 200 cm~(-1) region have been classified into three transitions, a ~4#PI#_(5/2)-X~2#DELTA#_(5/2), b ~4#PHI#_(7/2)-X~2#DELTA#_(5/2), and b ~4#PHI#_(5/2)-X~2#DELTA#_(5/2) with the 0-0 band origins near 8381.7, 11 147.9, and 12 127.2 cm~(-1), respectively. A rotational analysis of these bands provides the following equilibrium constants for the ground electronic state: #omega#_e = 1147.9492(77) cm~(-1), #omega#_ex_e = 5.4603(36) cm~(-1), B_e = 0.493 381(55) cm~(-1), #alpha#_e = 0.002 753(38) cm~(-1), and r_e = 1.618 023(91) A. Ab initio calculations have been performed on OsN and the spectroscopic properties of the low-lying electronic states have been calculated. Our assignments are supported by these calculations. The ground state of OsN has been identified as a ~2#DELTA#_i state consistent with the observations for the isoelectronic IrC molecule [Jansson et al., Chem. Phys. Lett. 4, 188 (1969); J. Mol. Spectrosc. 36, 248 (1970)]. The 1#sigma#~22#sigma#~21#pi#~41#delta#~33#sigma#~2 electron configuration has been proposed for the ground state and the configurations for the other low-lying electronic states have also been discussed. This work represents the first experimental or theoretical investigation of the electronic spectra of OsN.