High-resolution infrared spectrum of BrCN in the ν2 and ν1/2ν2 regions

FT infrared spectra of BrCN have been recorded in the region of the v(2) band near 340 cm(-1), the v(1) band near 580 cm(-1), and the 2v(2) band near 690 cm(-1) with a resolution between 2.9 and 4.7 X 10(-3) cm(-1). The vibrational levels (01(1)0), (10(0)0), (02(0)0), (02(2)0), (11(1)0), and (20(0)0) have been analyzed employing cold bands, hot bands, and new millimeter-wave transitions. Band-by-band polynomial analyses and a combined fit of all data relevant to the 2v(1) + v(2) = 2 polyad levels have been performed. The latter fit considered l-resonance interactions between the (02(0)0), e and (02(2)0), e levels and Fermi resonance between the two Sigma states (10(0)0) and (02(0)0). Altogether about 1000 pieces of data up to J = 100 were fitted for each of the two isotopic species with rms of the residuals of 2-8 x 10(-4) cm(-1) for the infrared and 10-120 kHz for the pure rotational data. (C) 2000 Academic Press.