THE A(1)DELTA(A2) STATES OF BICL, BIBR, AND BII

The emission spectra of the a(1)a(a2) --> X(2)l transitions of BiCl, B iBr, and BiI have been observed in the near-infrared spectral region n ear 2 mu m. The bismuth halide radicals were generated and excited in a fast-flow system by reaction of bismuth vapor (Bi-x,) with the halid es and microwave-discharged oxygen. The NIR chemiluminescence was meas ured with a Fourier-transform spectrometer equipped with Ge and InSb d etectors. The spectra contain the Delta v = +2, +1, 0, -1, and -2 sequ ences of the X(2)1 --> X(1)O(+) and the Delta v = 0 sequences of the a 2 --> X(2)1 transitions of the radicals. Vibrational analyses have yie lded improved molecular constants for the X(1)O(+) and X(2)1 ground st ate components and the following constants of the a2 states of the thr ee radicals (in cm(-1)): (BiCl)-Cl-35: T-e = 11 754.53(1), w(e) = 324. 22(1), w(e)x(e) = 1.063(2); (BiBr)-Br-79: T-e = 11 478.25(1), w(e) = 2 17.85(1), w(e)x(e) = 0.569(1); BiI: T-e = 10 874.62(5), w(e) = 166.23( 3), w(e)x(e) = 0.502(3), where the numbers in parentheses are the stan dard deviations of the parameters. (C) 1996 Academic Press, Inc.