THE A (3)SIGMA(+)(U) (A(1)1(U)) -] X (1)SIGMA(+)(G) (X0(G)(+)) TRANSITION OF SB-2

Chemiluminiscence of the a (3) Sigma(u)(+)(a(1)l(u)) -> X (1) Sigma(8)(+)(XO(8)(+)) transition of Sb-2 has been observed in the near-infrared spectral region between 6000 and 10000 cm(-1) from the afterglow of a microwave discharge in a mixture of antimony vapour and argon carrier gas in a fast-flow system. The spectrum consisting of short sequences of red-degraded bands was measured at a resolution of 0.5 cm(-1) with a Fourier-transform spectrometer. Vibrational analysis of the system has yielded the following molecular constants of the a(1)l(u) state of (SbSb)-Sb-121-Sb-123 (in cm(-1)): T-c = 9474.29(11), omega(e) = 205.717(58), omega(e) chi(e) = 0.554(16), where the numbers in parentheses give the standard deviations of the parameters in units of the last digit.