HIGH-RESOLUTION OSCILLATOR STRENGTH MEASUREMENTS OF THE CO B1#~1sum~+#-X#~1 sum~+# (0, 0) AND (1, 0) VIBRATIONAL BANDS

摘要

Large discrepancies in the published photoabsorption oscillator strengths of the vacuum-ultraviolet (VUV) bands of CO hamper the interpretation of VUV astronomical observations. We report new oscil- lator strength measurements of the (0,0) and (1,0) bands of the CO B #~1sun~+#-X#~sum~+# electronic system determined from high-resolution (resolving power approx.750,000) absorption spectra recorded with a tunable VUV laser system. The instrumental bandwidth (~0.14 cm-1 FWHM) was significantly less than the widths of the Doppler-broadened CO lines (~0.20 cm-1 FWHM). The B(0)-X(0) and B(1)-X(0) band oscillator strengths, derived from measurements of the photoabsorption cross sections of 36 individual rotational lines, are (6.5 ± 0.6) x 10-3 and (l.l ± 0.l) x 10-3, respectively. Our results are compared with other recent laboratory measurements and with ab initio calculations.