| Abstract: | Molecular constants for the E0+(3P2) and 1(3P2) ion-pair states of ICl vapor have been determined using sequential two-photon polarization-labeling spectroscopy. The two states are coupled by a heterogeneous perturbation which is analyzed in some detail for low-lying vibrational levels of 1(3P2). The I35Cl potential constants for the 1(3P2) state and the rotation-vibration constants for the set of f sublevels—i.e., the constants unaffected by coupling with the E state—are (in cm−1) 1(3P2): Y0,0= 39103.814(32), Y1,0= 170.213(15), Y2,0= −0.4528(22), Y3,0= −7.0(12) × 10−4, Y4,0= −1.48(24) × 10−5 and Y5,0= −6.6(19) × 10−8, Y(f)0,1= 5.6878(17) × 10−2 Y(f)1,1= −2.110(24) × 10−4, Y(f)2,1= −1.23(62) × 10−7, and Y(f)0,1= −3.08(22) × 10−8Likewise, the I35Cl constants determined for the E 0+(3P2) state are E 0+(3P2: Y0,0= 39054.38(61), Y1,0= 166.96(10), Y2,0 = −0.3995(42), Y0,1= 5.738(31) × 10−2, and Y1,1= −1.67(26) × 10−4Practical constraints in pumping the sequence E 0+ ← B 0+ ← × 0+ restrict the analysis of the E state to levels v = 9–15. Given the long extrapolation to the equilibrium state the 3σ statistical uncertainties quoted for these constants should be treated with caution. |
