IMPROVED SPECTROSCOPIC CONSTANTS FOR I-2-D-(1)SIGMA(+)(U)

The D-X transition of I-2 can be used to observe populations in vibrat ionally excited levels of I-2(X). Levels in the range 20 less than or equal to V '' less than or equal to 50 are sensitively detected by exc iting transitions that terminate on I-2(D) V' less than or equal to 40 . In the present work, spectroscopic studies of the lower vibrational levels of I-2(D) were performed to facilitate use of the D-X transitio n for monitoring excited I-2(X). New molecular constants for the D sta te are reported.