OPTICAL-OPTICAL DOUBLE-RESONANCE SPECTROSCOPY OF THE I-2 0(G)(+)((1)D) ION-PAIR STATE

The 0+g(1D) ion-pair state of I2 has been analyzed by optical-optical double-resonance using the 0+g(1D)-B3Π(0+u)-X1Σ+g photoexcitation sequence. The analysis of the 374 transitions in the 0 ≤ v ≤ 20 and 9 ≤ J ≤ 117 range yields a set of molecular parameters in a Dunham-type expansion: Y00 55 409.954(3), Y10 = 97.0979(11), Y20 = -0.19360(12), Y30 = 2.781(35) × 10-4, Y01 = 0.01815891(64), Y11 = -3.362(12)) × 10-5, Y21 = -1.65(66) × 10-8, and Y02 = -2.639(40) × 10-9 (all in cm-1 and σ in parentheses). An RKR potential is constructed based on these constants, and used to interpret the 0+g(1D)-B3Π(0+u) emission. We also observed a highly vibrational excited 0+g(3P0) state, whose molecular constants valid up to v = 101 are reported. © 1993 Academic Press, Inc.