Spectral simulation and interpretation of LiZn and LiCd blue-green emission

Abstract

Abstract. Excited LiZn and LiCd molecules are produced in a photochemical reaction between Li2(C lHu) molecules and zinc or cadmium atoms. Changes in shape of the blue-green emission are observed by increasing the total vapor pressure in the heat pipe oven. Quantum mechanical spectral simulations are carried out for the relevant 2 2H~X2S+ transitions. Both bound-bound and bound-free types of transitions are found to play an important role in the overall blue-green spectra. For high collision frequencies (high total vapor pressure) the simulated spectra show very good agreement with observations if a thermal distribution in the 2 2H states is assumed. In this case bound-bound transitions are dominant. The results for low collision frequencies indicate that the nascent distribution is non-Boltzmann and that bound-free transitions are dominant.

Rotational Analysis of the LiHg 22Π3/2–X2Σ+1/2 (v′ = 0 ← v" = 0, 1, 2) Vibronic Bands

“…Basically the spectrum is dominated by a strong vЈ ϭ 0 4 vЉ ϭ 0 transition. The vЈ ϭ 0 4 vЉ ϭ 1, 2 and the vЈ ϭ 1 4 vЉ ϭ 0 transitions are all reduced in intensity, which is in agreement with quantum mechanical calculations using the ab initio potential energy curves (6). To the blue of the previously reported v ϭ 1 4 vЉ ϭ 0 band, the vЈ ϭ 2 4 vЉ ϭ 0 band is also observed.…”

“…The upper sign (ϩ) in Eq. [6] applies to T c , the lower (Ϫ) to T d . T c represents e-symmetry ⌳ components, and T d the f-symmetry ⌳ components.…”

“…In the fit the energy term values for the excited electronic states (vЈ ϭ 0, 1) are represented by Eqs. [5], [6], and [7]. For the ground electronic state the energy term values are represented as the sum of two terms: a spin-rotation coupling term and the Dunham coefficients for the ground electronic state:…”

Resonance 2s-2p excitation of lithium in the Li + Cd system

“…The Li-Cd system has been studied extensively over the last few years. Blue-green diffuse bands of the LiCd molecule have been observed as a result of photochemical reactions [7][8][9]. Several other excitation paths have also been studied [10,11].…”

Quasiresonant Excitation of Lithium 2p–4d and 2p–4s Transitions in Li-Cd Vapor Mixture

“…Particularly the LiCd molecule has been ¢rst observed as a product of a photochemical reaction of the excited Li 2 C 1 P u or Li 2 (F 1 S g ) dimer and the ground state Cd atom [6,7]. The LiCd emission in the spectral region from 460 to 500 nm, with two distinct maxima at 482 nm and 489 nm was interpreted as resulting from the 2 2 P 3=2 ^X2 S 1=2 and the 2 2 P 1=2 ^X2 S 1=2 transitions, respectively [6,8]. Photoassociation of Li and Cd atoms into LiCd(2 2 P) is reported as well, for laser excitation in the region from 435 nm to 450 nm [9].…”