The spectrum and structure of the He_{2} molecule . Multichannel quantum defect analyses of the triplet levels associated with (1σ_{g})^{2}(1σ_{u})npλ</SBT>
Abstract
Emission spectra for the electronic transitions 617pπ ^{3}Π_{g}2s a ^{3}Σ_{u}^{+} and 716pσ ^{3}Σ_{g}^{+}2s a ^{3}Σ_{u}^{+} of He _{2} are reported and the electronic structures of npπ ^{3}Π_{g}^{} and np( ^{2}Σ_{g}^{+}, ^{3}Π_{g}^{+}) characterized. The energy levels associated with (1σ _{g}) ^{2}(1σ _{u})np( ^{3}Σ_{u}^{+}, ^{3}Π_{g}^{+}) exhibit extensive channel mixing, which leads to a breakdown of conventional band models for the higher n^{∗}members of these Rydberg "series." However, a model based on multichannel quantum defect theory quantitatively correlates the observed level structures. The higherenergy ( n ^{∗} > ∼5 ) portions of the np( ^{3}Σ_{g}^{+}, ^{3}Π_{g}^{+}) channels can be represented by two eigenquantum defects μ_{1} = 0.225 and μ_{2} = 0.930 and the close to loosecoupling matrix elements U _{11} = U _{22} = [N(2N + 1) ^{1}] ^{{1}/{2}} and U _{12} = U _{21} = [(N + 1)(2N + 1) ^{1}] ^{{1}/{2}}. The inclusion of energy dependence in the μ_{α}' s leads to quantitative correlations for all n^{∗}values.
 Publication:

Journal of Molecular Spectroscopy
 Pub Date:
 July 1980
 DOI:
 10.1016/00222852(80)90106X
 Bibcode:
 1980JMoSp..82..152G