A. Marjatta Lyyra

Determination of the long-range potential and dissociation energy of the 1 3Δg state of Na2

The 1u20093Δg state of Na2 has been studied extensively by both filtered fluorescence and ionization detection and analyzed by both Dunham‐type expansion and near‐dissociation expansion (NDE) models in the analysis. Our observations have covered 99.998% of the potential well depth with the outermost Rydberg–Klein–Rees (RKR) turning point at 28.02 A. NDE analysis gives Te=28u2009032.468 (±0.021) cm−1, De=7162.436 (±0.021) cm−1, and Re=3.463u200981 (±0.000u200928) A. Significant long‐range behavior in the near dissociation levels has been observed. Fitting of the RKR turning points gives the long‐range coefficients C5=1.388 (±0.031)×106 cm−1u2009A5 and C6=0.4008 (±0.0046)×108 cm−1u2009A6. These newly observed results show reasonable agreement with recent theoretical calculations.

Predissociation of the F(4) 1Σg+ state of Li2

This paper reports measurements of the homogeneous predissociation of the Li2 Fu200a1Σg+ state due to electrostatic interaction with the Eu200a1Σg+ state. Ab initio potential energy curves have been calculated for both states which in the adiabatic representation show two avoided crossings. However, predissociation was not previously predicted. Our experimental results show that the three isotopomers 7Li2, 6Li7Li, and 6Li2 all strongly predissociate above the 2s+3s atomic limit. We report high resolution measurements of linewidths for a large number of F–state levels spread across the 2600 cm−1 energy region between the 2s+3s and 2p+2p atomic limits, which yield systematic information regarding the rotational, vibrational, and isotopomer dependence of the predissociation rate. An experimental RKR potential energy curve for the F state is derived and used to calculate predissociation rates whose trends show good agreement with the experimental values. This paper presents the first complete data set of observations...

Born–Oppenheimer breakdown in a combined-isotopomer analysis of the A 1Σu+–X 1Σg+ system of Li2

New high resolution polarization data have been obtained for the A–X band system of 6,7Li2u200a, and new Fourier transform data for the homonuclear lithium dimers. They are combined with earlier data for 6,6Li2 and 7,7Li2u200a in the first systematic combined-isotopomer analysis of data for Li2u200a. This analysis of 8445 rovibrational transitions yields an improved and internally consistent set of molecular constant for the three Li2 isotopomers, and determines the electronic isotope shift and leading vibrational and rotational Born–Oppenheimer breakdown correction terms for both electronic states.

Electromagnetically induced transparency and dark fluorescence in a cascade three-level diatomic lithium system

at resonance implies that the molecules were trapped in the ground state. We used density matrix methods to simulate the response of an open molecular three-level system to the action of a strong coupling field and a weak probe field. The analytical solutions were obtained under the steady-state condition. We have incorporated the magnetic sublevel (M) degeneracy of the rotational levels in the lineshape analysis and report |M| dependent lineshape splitting. The theoretical calculations are in excellent agreement with the observed fluorescence spectra. We show that the coherence is remarkably preserved even when the coupling field was detuned far from the resonance.

Observation of the K2 43Δg state by cw perturbation-facilitated optical–optical double resonance spectroscopy

Abstract This paper reports for the first time both, an experimental observation and theoretical calculations of the K 2 4 3 Δ g state. For the experiment we used cw perturbation-facilitated optical–optical double resonance (PFOODR) spectroscopy. A single mode Ti-sapphire laser and a dye laser served as the pump and probe lasers, respectively. A total of 55 PFOODR signals have been assigned to the 4 3 Δ g xa0←xa0 b 3 Π u transitions. Absolute vibrational numbering was determined by using quantum defect analysis combined with comparing observed intensities with calculated Franck–Condon factors (FCF). For the former we used known parameters from the 2 3 Δ g state since the 2 3 Δ g and the 4 3 Δ g states belong to the same Rydberg series. We report here our experimental and calculated spectroscopic constants, the corresponding RKR potential energy curve, the Franck–Condon table for the 4 3 Δ g xa0↔xa0 b 3 Π u system, as well as a comparison with the theoretical potential energy curve. The T e value is found to be 28408.938(52)xa0cm −1 .

Assignment of the diabatic and adiabatic atomic asymptotic limits of K2 Rydberg states

In order to make an unambiguous assignment of the atomic asymptotic limits for the previously observed Rydberg states of K2, two more low‐lying Rydberg states (one 1Δg state and one 1Πg state), were observed with sub‐Doppler resolution using cw optical–optical double resonance spectroscopy. The correlation of the molecular Rydberg states with the diabatic and adiabatic atomic limits, the quantum defects, and the diabatic and adiabatic dissociation energies are discussed and the principal quantum number assignment of Broyer et al. reinforced.

Hyperfine structures of the 2 3Σg+, 3 3Σg+, and 4 3Σg+ states of Na2

The hyperfine structures of the 2 (3)Sigma(g) (+), 3 (3)Sigma(g) (+), and 4 (3)Sigma(g) (+) states of Na(2) have been resolved with sub-Doppler continuous wave perturbation facilitated optical-optical double resonance spectroscopy via A (1)Sigma(u) (+) approximately b (3)Pi(u) mixed intermediate levels. The hyperfine patterns of these three states are similar. The hyperfine splittings of the low rotational levels are all very close to the case b(betaS) limit. As the rotational quantum number increases, the hyperfine splittings become more complicated and the coupling cases become intermediate between cases b(betaS) and b(beta J) due to spin-rotation interaction. We present a detailed analysis of the hyperfine structures of these three (3)Sigma(g) (+) states, employing both case b(betaS) and b(beta J) coupling basis sets. The results show that the hyperfine splittings of the (3)Sigma(g) (+) states are mainly due to the Fermi-contact interaction. The Fermi contact constants for the two d sigma Rydberg states, the 2 (3)Sigma(g) (+) and 4 (3)Sigma(g) (+), are 245+/-5 MHz and 225+/-5 MHz, respectively, while the Fermi contact constant of the s sigma 3 (3)Sigma(g) (+) Rydberg state is 210+/-5 MHz. The diagonal spin-spin and spin-rotation constants, and nuclear spin-electronic spin dipolar interaction parameters of the 3 (3)Sigma(g) (+) and 4 (3)Sigma(g) (+) states are also obtained.

Quantum state‐selected photodissociation of K2(B 1Πu←X 1Σ+g): A case study of final state alignment in all‐optical multiple resonance photodissociation

Polarized emission resulting from the quantum state‐selected photodissociation of K2 through quasibound levels of the Bu20091Πu state has been studied experimentally by high‐resolution all‐optical triple resonance techniques, and theoretically by generalized quantum defect theory using the adiabatic/recoil model for the dissociation dynamics. Observation of alignment in the initial state (from the photopreparation steps) and in the photofragment (from the photodissociation step) provides detailed insight into the dynamical evolution. Excellent agreement between the theoretical calculations and the experimental results is shown.

New pair of mixed levels in 6Li7Li

Abstract A new pair of singlet–triplet A 1 Σ u + ∼ b 3 Π u mixed levels of 6Li7Li has been identified and used here as window levels in pulsed perturbation-facilitated optical–optical double resonance (PFOODR) experiments to study the high-lying triplet 2 3 Δ g state. The new mixed levels reported here enhance access to the high-lying triplet states through the expansion of the Franck–Condon overlap factor range, at the same time allowing for more reliable determination of rotational constants. New molecular constants of the 2 3 Δ g state are reported here.

Observations and analysis with the spline-based Rydberg–Klein–Rees approach for the 31Σg+ state of Rb2

Ro-vibrational term values of the 3(1)Σg (+) state of (85,85)Rb2 and (85,87)Rb2 and resolved fluorescence spectra to the A(1)Σu (+) state are recorded following optical-optical double resonance excitation. The experimental data are heavily perturbed, and as a result, the standard analysis based on Dunham series representation of the energy levels fails. The analysis is done via modeling the adiabatic potential function with the Rydberg-Klein-Rees potential constructed from the generalized smoothing spline interpolation of the vibrational energies Gv and rotational constants Bv.