Xe 2 gerade Rydberg states observed in the afterglow of a microplasma by laser spectroscopy of $a^3 {\rm \Sigma }_u^ + ( {1_u,O_u^ - })$a3Σu+(1u,Ou−) absorption in the green (545–555 nm) and near-infrared (675–800 nm)
Abstract
Bound←bound transitions of the Xe dimer at small internuclear separation (R < 4.0 Å) have been observed in the 545–555 nm and 675–800 nm spectral regions by laser spectroscopy in the afterglow of a pulsed Xe microplasma with a volume of ∼160 nl. Transient suppression of Xe2 $A^1 {\rm \Sigma }_u^ + ( {O_u^ + }) \to X^1 {\rm \Sigma }_g^ + ( {O_g^ + })$A1Σu+(Ou+)→X1Σg+(Og+) emission in the vacuum ultraviolet (∼172 nm), induced by laser excitation of ${\rm \Omega }_g \leftarrow a^3 {\rm \Sigma }_u^ + ( {1_u,O_u^ - })$Ωg←a3Σu+(1u,Ou−) [Rydberg←Rydberg] transitions of the molecule, has confirmed the existence of structure between 720 and 770 nm (reported by Killeen and Eden [J. Chem. Phys. 84, 6048 (1986)]) but also reveals red-degraded vibrational bands extending to wavelengths beyond 800 nm. Spectral simulations based on calculations of Franck-Condon factors for assumed ${\rm \Omega }_g \leftarrow a^3 {\rm \Sigma }_u^ + $Ωg←a3Σu+ transitions involving Ω = 0±,1 gerade Rydberg states suggest that the upper level primarily responsible for the observed spectrum is an Ω = 1 state correlated, in the separated atom limit, with Xe(5p6 1S0) + Xe(5p5 6p) and built on a predominantly A2Π3/2g molecular ion core. Specifically, the spectroscopic constants for the upper state of the $1_g \leftarrow 1_u,O_u^ \pm $1g←1u,Ou± absorptive transitions are determined to be Te = 13 000 ± 150 cm−1, $\omega _e^\prime = 120 \pm 10\,{\rm cm}^{ - 1} $ωe′=120±10 cm −1, $\omega _e^\prime x_e^\prime = 1.1 \pm 0.4\,{\rm cm}^{ - 1} $ωe′xe′=1.1±0.4 cm −1, De = 3300 ± 300 cm−1, and ${\rm \Delta }R_e = R_e^\prime - R_e^{\prime \prime } = 0.3 \pm 0.1\ {\rm {\AA}}$ΔRe=Re′−Re″=0.3±0.1Å which are in general agreement with the theoretical predictions of the pseudopotential hole-particle formalism, developed by Jonin and Spiegelmann [J. Chem. Phys. 117, 3059 (2002)], for both the (5)1g and $( 3)O_g^ + $(3)Og+ states of Xe2. These spectra exhibit the most extensive vibrational development, and provide evidence for the first molecular core-switching transition, observed to date for any of the rare gas dimers at small R (<4 Ǻ). Experiments in the green (545–555 nm) also provide improved absorption spectra, relative to data reported in 1986 and 1999, associated with Xe2 Rydberg states derived from the Xe(7p) orbital.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jun 28, 2014
- Source ID
- 10.1063/1.4884606
Entities
People
- C. J. Wagner
- James Gary Eden
- T. C. Galvin
Organizations
- Air Force Office of Scientific Research
- University of Illinois Urbana–Champaign