Photodissociation of PbI2 in the ultraviolet: Analysis of the A → X band of PbI

G. Rodriguez, C. M. Herring, R. D. Fraser, J. G. Eden

Research output: Contribution to journalArticlepeer-review


Emission and absorption studies of lead moniodide (PbI) have been carried out by photodissociation of PbI2 vapor at one of several wavelengths (193, 248, 266, 308, and 351 nm) in the ultraviolet. Strong emission on the A → X 2Π1/2 band (14 400-22 800 cm-1; 440 ≲ λ ≲ 695 nm) occurs when PbI2 is photodissociated at 248 or 266 nm. Also, absorption bands attributed to the B ← X 2Π1/2,3/2, D ← X 2Π1/2,3/2, and E ← 2Π1/2,3/2 transitions of the diatomic molecule have been observed at 290 and 380, 225 and 265, and 203 and 240 nm, respectively, as have emission bands peaking at 397.6, 531.6, 582.0, 595.1, 639.7, 685.9, and 707.9 nm that appear to arise from PbI2 itself. Analysis and computer simulations of the A → X 2Π1/2 emission spectra have resulted in identifications for virtually all (>120) of the observed vibrational bandheads. Several spectroscopic constants for the A and the X 2Π1/2 states of PbI have been determined to be Te(A) = 20 659 ± 130 cm-1, ωe′ = 132.2 ± 1.0 cm-1, ωe′Xe′ = 1.91 ± 0.06 cm-1, ωe″ = 160.3 ± 0.6 cm-1, and ωe″xe″ = 0.24 ± 0.03 cm-1. Also, the difference between the equilibrium internuclear separations for the X 2Π1/2 and the A states has been determined to be ΔRe = 0.45 ± 0.05 Å. The spontaneous-emission lifetime for the PbI(A) state and the rate constant for quenching of this state by PbI2 (in two-body collisions) have been measured to be (94.3 ± 8.8) ns and (4.3 ± 0.4) × 10-10 cm3 s-1, respectively.

Original languageEnglish (US)
Pages (from-to)1362-1371
Number of pages10
JournalJournal of the Optical Society of America B: Optical Physics
Issue number7
StatePublished - Jul 1996

ASJC Scopus subject areas

  • Statistical and Nonlinear Physics
  • Atomic and Molecular Physics, and Optics


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