Spectroscopic study of the E 1Σ+g ‘‘shelf’’ state in 7Li2

Abstract

The E 1Σ+g ‘‘shelf ’’ state of the 7Li2 molecule was investigated using a pulsed optical optical double resonance technique. The measurements cover the vibrational levels in the range 0≤v≤29 including the shelf region around 13≤v≤15. Molecular constants have been determined. Using an inverted perturbation approach, an effective potential energy curve has been generated within the adiabatic approximation whose quantum mechanical energy eigenvalues reproduce all the measured term values to within 0.113 cm−1 for the range 0≤v≤23 and 0≤J≤47.

Algebraic vs. numerical methods for analysing diatomic spectral data: a resolution of discrepancies

“…(9), and the coefficients Z A;B l;m ¼ Z A;B l;m ðr e ; l; fc j g; fs A;B j g; ft A;B j g; fu A;B j gÞ are small terms which also depend on the expansion coefficients for the adiabatic and non-adiabatic radial strength functions. With the energy eigenvalues involved in the observed transitions represented by Eq.…”

“…However, over the past dozen years some uncertainty regarding the validity of this direct-potential-fit procedure has been raised by a persistent dispute about the validity and physical significance of the results yielded by two different approaches to the problem. One of these is a numerical approach, initially developed for treating triatomic Van der Waals molecules [4], which has been extensively applied to diatomic molecules by a number of research groups [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. The other is the algebraic approach applied in OgilvieÕs RADI-ADI-ATOM ATOM code [22][23][24][25][26][27][28][29][30][31][32].…”

Observations and spectral simulations of the7Li2 21 Σ u + →X 1 Σ g + transition

“…Recently Bernheim et al have used the optical-optical double resonance (OODR) method to study the highlying (E, F)127+, G 1/-/+ states using real levels of the A 127+ state as intermediate stage [21]. Applying the same two photon excitation method and using appropriate IR laser for stimulated emission pumping [22] the molecules could be prepared in the levels of the outer well or in the levels above the potential barrier of the double minimum state.…”

The Perturbation between the G1Π and 21Δ States of 7Li2

“…The E(3) 1 ⌺ g ϩ state dissociates to the 2s ϩ 3s atomic limit and was observed by Bernheim et al (1,4). The F (4) 1 ⌺ g ϩ state dissociates to the 2p ϩ 2p atomic limit and has been studied by pulsed OODR (1,5) and cw OODR spectroscopy (6).…”