| Abstrakt: |
Vibrationally and isotopically resolved fluorescence excitation spectra of Xe2 at 1300, 1485, and 1500 Å have been obtained and analyzed. They correspond to electronic transitions from the van der Waals ground state to the three lowest excited states. Molecules of Xe2 were formed in the v‘=0 level of the ground state using a pulsed supersonic jet, and fluorescence emission was excited by a tunable, coherent, and monochromatic source of vacuum ultraviolet radiation generated by four-wave-sum-mixing in Mg and Zn vapors. For each of the three band systems, unambiguous assignment of upper-state vibrational quantum numbering was possible, resulting in the determination of accurate upper-state spectroscopic constants for the first time. From system I (at ∼1500 Å) with bands v’=36 to 43, constants for the A1u state of 129,132Xe2 were found to be T’e =63 089.9(6.9), ωe =137.48(34), ωex’e =1.1668(43), and De =4174.4(7.5) cm-1. Band system II (at ∼1485 Å) with bands v’=35 to 46, gave constants for the B0+u state: T’e =63 795.6(4.2), ωe =124.85(20), ωex’e =0.9372(24), and De =4446.3(5.2) cm-1. Finally, system III (at ∼1300 Å) and bands v’=16 to 27 yielded the following constants for the C0+u state: T’e =75 881.7(1.5), ωe =49.71(10), ωex’e =0.4222(41), and De =1500.0 (3.4) cm-1. Potential curves based on these constants were calculated for all three excited states. [ABSTRACT FROM AUTHOR] |
