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Rotationally resolved Fourier-transform spectra of laser-induced fluorescence A 1 Σ u + ∼ b 3 Π u → X 1 Σ g + of K2 molecules were recorded and analyzed, yielding 4053 term values of the spin–orbit (SO) coupled A ∼ b complex of the 39K2 isotopologue with ∼0.01 cm−1 accuracy. Their compilation with 1739 term values from previously published sources allowed them to cover the energy range [9955, 17 436] cm−1 from the bottom of the lower-lying b3Πu state up to the vicinity of the atomic asymptote 4 s 2 S 1 2 + 4 p 2 P 1 2 , with a rotational quantum number J ∈ [0, 149]. The experimental data were processed by a direct 6 × 6 coupled-channel (CC) deperturbation treatment, which accounted explicitly for both SO and electronic-rotational interactions between all six e-symmetry states: A 1 Σ u + ( 0 u + ), b3Πu( 0 u + , 1 u , 2 u ), c3Σu(1u), and B1Πu(1u). The initial parameters of the global deperturbation model have been estimated in the framework of ab initio electronic structure calculations applying multi-reference configuration-interaction and coupled-clusters methods. The interatomic potentials analytically defined for A and b states, as well as SO-splitting of the triplet b state and A ∼ b SO-coupling functions, have been particularly refined to fit the 5792 term values of the 39K2 isotopologue, whereas the rest parameters were fixed on their ab initio values. The resulting mass-invariant parameters of the 6 × 6 CC model reproduced the overall rovibronic term energies of the A ∼ b complex of 39K2 with accuracy, which is well within the experimental errors. The quality of the deperturbation analysis was independently confirmed by comparison with the present obtained 705 and 14 term values of respective 39K41K and 41K2 isotopologues, as well as by agreement between measured and predicted relative intensity distributions in long A ∼ b → X(vX) band progressions. This deperturbation analysis provided the refined dissociation energy Tdis = 17 474.569(5) cm−1 and the long-range coefficient C 3 Σ = 5.501(4) × 105 cm−1 Å3 relevant to the non-relativistic atomic limit 4s + 4p. The derived Tdis yielded the accurate well depth De = 4450.910(5) cm−1 for the ground X 1 Σ g + state, whereas the new C 3 Σ value yielded the improved estimates for atomic K(4 p 2 P 1 2 ; 3 2 ) radiative lifetimes, τ 1 2 = 26.67(3) and τ 3 2 = 26.32(3) ns. [ABSTRACT FROM AUTHOR]

The oscillation continuum in laser-induced fluorescence spectra of bound-free c3Σ+ → a3Σ+ and (4)1Σ+ → X1Σ+ transitions of the KCs molecule was recorded by a Fourier-transform spectrometer and modeled under the adiabatic approximation. The required interatomic potentials for ground a3Σ+ and X1Σ+ states were reconstructed in an analytical Chebyshev-polynomial-expansion form in the framework of the regularization direct-potential-fit procedure based on the simultaneous consideration of experimental line positions from Ferber et al. [Phys. Rev. A 80, 062501 (2009)] and the present ab initio calculation of short-range repulsive potential data. It was proved that the repulsive part over the dissociation limit of the derived a3Σ+ potential reproduces the experiment better than the potentials reported in the literature. It is also shown that all empirical and semi-empirical potentials available for the X1Σ+ state reproduce the bound-free (4)1Σ+ → X1Σ+ spectrum with equal quality in the range of observations. [ABSTRACT FROM AUTHOR]

Fourier-transform A¹Σ+ − b³Π → X¹Σ+laser-induced fluorescencespectra were recorded for the natural mixture of 39,41K85,87Rb isotopologues produced in a heatpipe oven. Overall 4200 rovibronic term values of the spin-orbit coupled A¹Σ+ and b³Π states were determined with an uncertainty of about 0.01 cm-1 in the energy range [10 850, 14 200] cm-1 covering rotational quantum numbers J′ ∈ [3, 280]. Direct deperturbation analysis of the A ~ b complex performed within the framework of the A¹Σ+ ~ b³ΠΩ=0,1,2 coupled-channel approach reproduced experimental data with a standard deviation of 0.004 cm-1. Initial parameters of the internuclear potentials and spin-orbit coupling functions along with the relevant transition dipole moments were obtained by performing the quasi-relativistic electronic structure calculations. The mass-invariant molecular parameters obtained from the fit were used to predict energy and radiative properties of the A ~ b complex for low J levels of 39K85Rb as well as for 41K87Rb isotopologues, allowing us to identify the most reasonable candidates for the stimulated Raman transitions between the initial uppermost vibrational levels of the a³Σ+ and X¹Σ+ states, the intermediate levels of the A ~ b complex, and the lowest absolute ground X¹Σ+(v = 0, J = 0) state. [ABSTRACT FROM AUTHOR]

The paper presents an empirical pointwise potential energy curve (PEC) of the (2)¹π state of the KCs molecule constructed by applying the Inverted Perturbation Approach routine. The experimental term values in the energy range E{v',J') Ɛ [15407; 16579] cm-1 involved in the fit were based on Fourier-Trans form spectroscopy data obtained with 0.01 cm-1 accuracy from the laser-induced (2)¹π→ X¹Σ+fluorescence spectra. Buffer gas Ar was used to facilitate the appearance of rotation relaxation lines in the spectra, thus enlarging the (2)¹]π data set and allowing determination of the A-splitting constants. The data set included vibrational v' Ɛ [0,28] and rotational J' Ɛ [7,274] quantum numbers covering about 67% of the potential well. The present PEC reproduces the overall set of data included in the fit with a standard deviation of 0.5 cm-1. The obtained value of the A-doubling constant q = +1.8 × 10-6 cm-1 for J' > 50 and v' Ɛ [0,6] is in an excellent agreement with q = +1.84 × 10-6 cm-1 reported in Kim, Lee, and Stolyarov [J. Mol. Spectrosc. 256, 57-67 (2009)]. [ABSTRACT FROM AUTHOR]

The article presents a study of the strongly spin-orbit coupled singlet A ¹Σ+ and triplet b³∏ states of the RbCs molecule, which provide an efficient optical path to transfer ultracold molecules to their rovibrational ground state. Fourier-transform A ¹Σ+ - b³∏ → X ¹Σ+ and (4)¹Σ+ → A ¹Σ+ - b³∏ laser-induced fluorescence (LIF) spectra were recorded for the natural mixture of the 85Rb133Cs and 87Rb133Cs isotopologues produced in a heat pipe oven. Overall 8730 rovibronic term values of A ¹Σ+ and b³∏ states were determined with an uncertainty of 0.01 cm-1 in the energy range [9012, 14087] cm-1, covering rotational quantum numbers J ∈ [6, 324]. An energy-based deperturbation analysis performed in the framework of the four A ¹Σ+ - b³∏Ω=0,1,2 coupled-channels approach reproduces 97% of the experimental term values of both isotopologues with a standard deviation of 0.0036 cm-1. The reliability of the deperturbed mass-invariant potentials and spin-orbit coupling functions of the interacting A ¹Σ+ and b³∏ states is additionally proved by a good reproduction of the A - b → X and (4)¹Σ+ → A - b relative intensity distributions. The achieved accuracy of the A - b complex description allowed us to use the latter to assign the observed (5)¹Σ+ → A - b and (3)¹∏ → A - b transitions. As is demonstrated, LIF to the A - b complex becomes as informative as to the ground X ¹Σ+ state, which is confirmed by comparing the results of (4)¹Σ+ state analysis based on (4)¹Σ+ → A - b LIF with the data from V. Zuters et al. [Phys. Rev. A87, 022504 (2013)] based on (4)¹Σ+ → X LIF. [ABSTRACT FROM AUTHOR]

High resolution Fourier-transform spectroscopy data of term values in the spin-orbit (SO) coupled first excited A 1Σ+ and b 3Π states in KCs were obtained from (4)1Σ+ → A 1Σ+ - b 3Π, A 1Σ+ - b 3Π → X1Σ+, and (1)3Δ1→b3Π0± spectra of laser-induced fluorescence (LIF). About 3000 new rovibronic term values of the A 1Σ+ and b 3ΠΩ states were obtained with an uncertainty about 0.01 cm-1 and added to the previously obtained 3439 term values in Kruzins et al. [Phys. Rev. A 81, 042509 (2010)] and 30 term values of the b 3Π0+ state levels below the A 1Σ+ state in Tamanis et al. [Phys. Rev. A 82, 032506 (2010)]. The data field was extended considerably, going down to vibrational level vb = 0 and up in energy to 13 814 cm-1, as compared to previously achieved vb = 14 and E = 13 250 cm-1. Overall 6431 e-symmetry term values of 39K133Cs were included in 4 × 4 coupled-channel deperturbation analysis. The analytical Morse-Long-Range (MLR) function yielded empirical diabatic potentials for the A 1Σ+ and b 3Π0+ states while the morphing of the SO ab initio points [J. T. Kim et al., J. Mol. Spectrosc. 256, 57 (2009)] provided the empirical diagonal and off-diagonal SO functions. Overall 98.5% of the fitted term values were reproduced with a rms (root mean square) uncertainty of 0.004 cm-1. The reliability of the model is proved by a good agreement of predicted and measured term values of the 41K133Cs isotopologue, as well as of measured and calculated intensities of (4)1Σ+ → A 1Σ+ - b 3Π LIF progressions. Direct-potential-fit of low-lying vb levels of the b 3Π0- component yielded the MLR potential which represents the 204 f-symmetry experimental term values with a rms uncertainty of 0.002 cm-1. The Ω-doubling of the b 3Π0 sub-state demonstrates a pronounced vb-dependent increase. [ABSTRACT FROM AUTHOR]

The Fourier transform spectrometer with resolution of 0.03 cm-1 was applied to disperse the diode laser induced B(1)1Π → X1Σ+ fluorescence spectra of the RbCs molecule in a heat pipe. The presence of buffer gas (Ar) produced in the spectra the dense pattern of collision-induced rotation relaxation lines, thus enlarging the B(1)1Π data set, allowing to determine the Λ-splitting constants and to reveal numerous local perturbations. In total, 2664 term values for 85Rb133Cs and 87Rb133Cs in the energy range from 13 770 to 15 200 cm-1 were obtained with accuracy about 0.01 cm-1. A pointwise potential energy curve (PEC) based on inverted perturbation approach was constructed in the R-range from 3.35 to 9.00 Å for less perturbed vibrational levels v′ ∈ [0, 35] and compared with ab initio calculations. The data included in the fit were reproduced by present PEC with standard deviation (sd) 0.95 cm-1. More systematic over rotational levels J′ ∈ [6, 228] data set was obtained for v′ ∈ [0, 2]. These data were reproduced by the obtained PEC with sd of 0.08 cm-1. The energy of PEC's minimum Te = 13 746.65 cm-1, as well as other main molecular constants were determined. [ABSTRACT FROM AUTHOR]

The diode laser induced B(1)1Π → X1Σ+ fluorescence spectra of the KCs molecule were recorded by Fourier-transform spectrometer with resolution of 0.03 cm-1. Buffer gas Ar was used to facilitate appearance of rotation relaxation lines in the spectra, thus enlarging the B(1)1Π dataset, allowing one to determine the Λ-splitting constants and to reveal numerous local perturbations. A dataset was systematically obtained for B(1)1Π vibrational levels v′ ∈ [0; 5] nonuniformly covering rotational levels with J′ ∈ [7; 233]. For v′ ∈ [0; 3], the less-perturbed data of f-components were included in the fit. A pointwise potential energy curve (PEC) based on the inverted perturbation approach, as well as the Dunham coefficients, was obtained and compared with ab initio calculations; in particular, the energy of the PEC's minimum Te = 14 044.918(6) cm-1 was determined. Both approaches allowed us to reproduce the vast majority of data used in the fit with accuracy of 0.02 cm-1. Tentative molecular constants for several vibrational levels of the near lying C(3)1Σ+ state were estimated. [ABSTRACT FROM AUTHOR]

The paper presents high-resolution experimental study and a direct potential construction of a shelflike state E(4)1Σ+ of the KCs molecule converging to K(42S) + Cs(52D) atomic limit; such data are of interest for selecting optical paths for producing and monitoring cold polar diatomics. The collisionally enhanced laser induced fluorescence (LIF) spectra corresponding to both spin-allowed E(4)1Σ+ → X(1)1Σ+ and spin-forbidden E(4)1Σ+ → a(1)3Σ+ transitions of KCs were recorded in visible region by Fourier transform spectrometer with resolution of 0.03 cm-1. Overall about 1650 rovibronic term values of the E(4)1Σ+ state of 39K133Cs and 41K133Cs isotopologues nonuniformly covering the energy range [16987, 18445] cm-1 above the minimum of the ground X-state were determined with the uncertainty of 0.01 cm-1. Experimental data field is limited by vibrational levels v′ ∈ [2, 74] with rotational quantum numbers J′ ∈ [1, 188]. The closed analytical form for potential energy curve (PEC) based on Chebyshev polynomial expansion (CPE) was implemented to a direct potential fit (DPF) of the experimental term values of the most abundant 39K133Cs isotopologue. Besides analyticity, regularity, correct long-range behavior, and nice convergence properties, the CPE form demonstrated optimal balance on flexibility and constraint for the DPF of a shelflike state aggravated by a limited data set. The mass-invariant properties of the CPE PEC were tested by the prediction of rovibronic term values of the 41K133Cs isotopomer which coincided with their experimental counterparts with standard deviation of 0.0048 cm-1. The CPE modeling is compared with the highly flexible pointwise inverted perturbation approach model, as well as with conventional Dunham analysis of restricted data set v′ <= 50. Reliability of the empirical PEC is additionally confirmed by good agreement between the calculated and experimental relative intensity distributions in the long E(v′) → X(v″) LIF progressions. [ABSTRACT FROM AUTHOR]

We present here the first analysis of laser induced fluorescence (LIF) of the KCs molecule obtaining highly accurate data and perform a direct potential construction for the X 1Σ+ ground state in a wide range of internuclear distances. KCs molecules were produced by heating a mixture of K and Cs metals in a heat pipe at a temperature of about 270 °C. KCs fluorescence was induced by different laser sources: the 454.5, 457.9, 465.8, and 472.7 nm lines of an Ar+ laser, a dye laser with Rhodamine 6G dye (excitation at around 16 870 cm-1), and 850 and 980 nm diode lasers (11 500–11 900 and 10 200–10 450 cm-1 tuning ranges, respectively). The LIF to the ground state was recorded by a Bruker IFS-125HR Fourier transform spectrometer with a spectral resolution of 0.03 cm-1. Particularly, by applying the 850 nm laser diode we were able to observe LIF progressions to very high vibrational levels of the ground state close to the dissociation limit. The present data field contains 7226 term values for the ground state X 1Σ+ and covers a range from v″=0 to 97 with J″ varying from 12 to 209. More than 10 000 fluorescence lines were used to fit the ground state potential energy curve via the inverted perturbation approach procedure. The present empirical potential extends up to approximately 12.6 Å and covers more than 99% of the potential well depth, it describes most of the spectral lines with an accuracy of about 0.003 cm-1 and yields a dissociation energy of 4069.3±1.5 cm-1 for the ground state X 1Σ+. First observations of the triplet ground state a 3Σ+ of KCs are presented, and preliminary values of few main molecular constants could be derived. [ABSTRACT FROM AUTHOR]

The lowest 1Π state of the NaCs molecule, the B(1)1Π state, was studied using a dye laser for inducing fluorescence that was resolved by a high resolution Fourier-transform spectrometer. The presence of argon buffer gas yielded rich rotational relaxation spectra allowing to enlarge the data set for the B(1)1Π state, to obtain Λ-splittings and to reveal numerous local perturbations. 543 weakly perturbed energy levels for rotational quantum numbers from J′=5 to 168 and vibrational quantum numbers from v′=0 to 25, which cover about 87% of the potential well depth, were used for a direct pointwise fit of the potential energy curve applying the inverted perturbation approach method. The resulting potential reproduces the term values for v′=0–7 with an experimental accuracy of about 0.01–0.02 cm-1, whereas for v′=8–25 the deviations increase due to the perturbations, going to the order of 1 cm-1; an extrapolation is made to the dissociation asymptote. [ABSTRACT FROM AUTHOR]

We present experimental data on the electric permanent dipole moments d(υ′,J′) and Λ splittings (q factors) in the quasidegenerate (3) 1Πe/f state of the NaCs molecule over a wide range of the vibrational (υ′) and rotational (J′) quantum numbers by using the combination of dc Stark mixing and electric radio frequency-optical double resonance methods. Within the experimental (3) 1Π state υ′ ranged from υ′=0 to 34, q values exhibited a pronounced decrease from 7.91×10-6 to 0.47×10-6 cm-1, while |d| values varied between 8.0 and 5.0 D. Experimental evaluation yielded small d values about 1 D for D(2) 1Π state υ′<3 levels. The experiment is supported by ab initio electronic structure calculations performed for the (1–3) 1Π states of NaCs by means of the many-body multipartitioning perturbation theory of potential energy curves, permanent dipole, and angular coupling matrix elements for the lowest singlet states. The predicted d values reproduce their experimental counterparts within the measurement errors while theoretical q factors reproduce the measured υ′ dependence being, however, systematically overestimated by ca. 1×10-6 cm-1. The present NaCs data are compared with those of the NaK and NaRb molecules. [ABSTRACT FROM AUTHOR]

The (3)1Π state of the NaCs molecule was studied by high resolution Fourier-transform spectroscopy. The (3)1Π→X 1Σ+ laser induced fluorescence was excited by an Ar+ ion laser or by a single-mode frequency-doubled cw Nd:YAG laser. The presence of argon buffer gas yielded rich rotational relaxation spectra allowing to enlarge the data set for the (3)1Π state term values, as well as to observe Λ splittings in a wide range of vibrational (v′) and rotational (J′) quantum numbers. The data field includes about 820 energy levels of (3)1Π NaCs in the range from v′=0 to 37 and from J′=3 to 190, which corresponds to ca. 95% of the potential well depth. Direct fit of the potential energy curve to the level energies is realized using the inverted perturbation approach method; a set of Dunham coefficients is also presented. [ABSTRACT FROM AUTHOR]

The paper presents the study of the fully mixed A ¹Σ[sup +] -b ³Π complex of the NaRb molecule based on high-resolution sub-Doppler spectroscopy and intensity measurements, ab initio relativistic calculations of energies, transition moments and spin-orbit interactions, as well as an inverted channel-coupling approach (ICCA) deperturbation analysis. A two-laser V-type pump-probe excitation scheme was employed to obtain A←X transition frequencies to 16 A-state vibrational levels from v = 6 to v = 21 with J from 8 to 23. Additionally, relative intensities in laser-induced A→X fluorescence spectra have been recorded, including progressions with all observable transitions to the ground state vibronic levels, the latter yielding unambiguous v assignment of the A-state levels observed. All experimental rovibronic term values and all measured intensity distributions were embedded in a direct simultaneous weighted nonlinear fitting in the framework of an elaborated ICCA allowing us to obtain deperturbed relativistic diabatic potentials of the interacting A ¹Σ[sup +] and b ³Π states. To make this possible, ab initio structure calculations of the spin-orbit singlet-triplet coupling parameter, the spin-orbit splitting of the b ³Π state, the transition dipole moments, and the electronic energy differences for internuclear distance 3.0-7.0 Å have been performed using second order many-body multipartitioning perturbation theory. The developed ICCA is proved to be appropriate for deperturbation analysis of strongly coupled electronic states provided that accurate nonadiabatic matrix elements are known. This allows unambiguous assignment of the vibrational levels of the b ³Π[sub 0] state, which is not directly observed. [ABSTRACT FROM AUTHOR]

We discuss quantum beats in electronically excited molecular states with high rotational angular momenta J appearing in time resolved fluorescence in conditions of quadratic and linear energy shift dependence on magnetic quantum number M and external field strength. Density matrix formalism is used to obtain in explicit form the expressions for time dependent fluorescence intensity after δ-function pulsed excitation. In case of pure quadratic Stark effect, which is typical for 1Σ state diatomics, excited state quantum beats for J>1 exhibit a regular, or ‘‘grill’’ structure, consisting of narrow equidistant ‘‘principal’’ peaks with equal relative amplitudes on the exponential decay background. At linear polarized excitation the time intervals between the adjacent peaks are 2π/ω20, ω20 being the splitting frequency between coherently excited M-sublevels with M=2 and M’=0. If an admixture of linear contribution is present in field induced level shifts, the grill structure is superimposed by a single frequency harmonic modulation. A special geometry was found in which the quadratic beats are fully absent and the modulated grill pattern is brought into existence only by the influence of linear term. Such a case takes place when the light polarization vector in fluorescence is directed at 45° angle with respect to the exciting light polarization vector and yields the most sensitive way to separate quadratic and linear contribution. We considered the examples when the first order term appears by a combined action of electric and magnetic field, as well as due to the e–f level electric field induced mixing, with the parameters typical for the NaK molecule. [ABSTRACT FROM AUTHOR]

General conditions causing partial transformation of optical alignment of excited state angular momenta J into orientation at weak linear polarized broad line excitation of molecules are examined. As is shown, the phenomenon takes place under the effect of an external perturbing factor leading to such magnetic sublevel M splitting ω[sub MM′] when ω[sub MM±1]≠ω[sub -M≠1-M] and ω[sub MM′] is of the order of molecular state relaxation rate. An analytical expression is obtained describing the appearing circularity of fluorescence for arbitrary J values. A numeric example is given for [sup 1]∑ state molecules with J=10 assuming a quadratic Stark effect in a homogeneous external electric field. [ABSTRACT FROM AUTHOR]

The paper analyzes magnetic field induced alignment–orientation conversion (AOC) phenomenon caused by simultaneous effect of quadratic terms in Zeeman energy shift and magnetic predissociation (PD), producing asymmetry either in energy splitting ωMM±1≠ω-M∓1-M or in relaxation of coherence ΓMM±1≠Γ-M∓1-M between coherently excited M, M±1 magnetic sublevels. The AOC is registered via the appearance of circular polarization (C) of fluorescence under linearly polarized excitation. The unified perturbation treatment of a molecule in external magnetic field B is presented, accounting for magnetic and intramolecular perturbations via interaction with bonded or continuum states, considering Hund’s (c)-case coupling and dividing the intramolecular perturbation operator into homogeneous (ΔΩ=0) and heterogeneous (ΔΩ=±1) parts. Explicit expressions up to B2 terms are given for energy shift and PD rate, adapted to 1u state in conditions relevant to the B 3Σ-u complex of Te2 molecule. Numeric simulation revealed that nonlinear magnetic energy shift and heterogeneous magnetic PD produce dispersion type fluorescence circularity signals C(B) of different sign. Fitting of experimental data on B1-u, v(J)=2(96) state of 130Te2 molecule allowed to determine the electronic matrix element of paramagnetic Hamiltonian (Ω=0|Ĥpm|Ω=1)≡G±=2.7, as well as the natural Cvhet=±6 s-1/2 and the magnetic αvhet=∓9×103 s-1/2 T-1 rate constants of heterogeneous PD, supposing that the B1-u state PD takes place through 0-u state continuum. As a result, magnetic AOC represents a sensitive method to investigate molecular structure and intramolecular interaction between both bonded and continuum states. Additionally, it has been shown that the magnetic PD effect leads to strong amplification of nonzero field level crossing signals caused by B2 terms... [ABSTRACT FROM AUTHOR]

In the framework of a unified physical model, employed as a basis Hund’s case ‘‘c,’’ a quantitative description has been worked out for experimental data of term values, g factors, and lifetimes of excited B0+u and A1u states, as well as for relative intensities in B0+u–X0+g, A1u–X1g, and B0+u–X1g transitions. The model includes a minimum number of adjustable fitting parameters: deperturbed molecular constants for both states, intramolecular interaction matrix element (η), two electronic matrix elements of magnetic interactions (Gz,G±), as well as two parallel (Re||B0u+–X0g+, Re||A1u–X1g) and two perpendicular (Re⊥B0u+–X1g, Re⊥A1u–X0g+) electronic transition moments. The B0+u state g factors and the intensity distribution over P, R, Q branches in B0+u–X1g transition was found to be most sensitive to weak heterogeneous (ΔΩ=±1) perturbations, and a simple analytic connection between those characteristics has been proposed. The Ω-doubling constant for A1u state levels was evaluated. By transforming the responsible electronic matrix elements to Hund’s case ‘‘a’’ basis, the A1u state has been found to be basically a 3Σ1 component of the B 3Σ-u state, with a small admixture (<14%) of a 3Π1 component of the A 3Πu state, and a change in term notation from A1u to B1u is proposed. [ABSTRACT FROM AUTHOR]

This paper reports the observation of the molecular fluorescence circularity under irradiation with linear polarized light. The phenomenon arises as a result of partial transformation from alignment of the ensemble of molecular angular momenta into orientation due to quadratic correction to Zeeman effect. Circularity rate up to 0.05 at magnetic field 0.4 T was registered in B 3Σu-(1u-)→X 3Σg-(1g-) fluorescence of 130Te2 molecules at angle π/4 with respect to Ê vector of linear polarized exciting light. Quadratic magnetic energy terms are associated with magnetic field induced ΔJ=±1 e/f mixing between 1u-∼1u+ and 1u-∼0u+ states. Circularity data fitting shows that the electronic part of Landé factor caused by 1u-∼0u+ interaction is equal to G± [bar_over_tilde:_approx._equal_to]gl<0u|Ja±|1u>+(gs-gl) <0u|S±|1u>[bar_over_tilde:_approx._equal_to]2.72. [ABSTRACT FROM AUTHOR]

The b 3Πu–A 1Σu+ interaction in Na2 as manifested by A 1Σu+ state Lande factors was investigated. Landé factors gA were measured from the dispersion shape Hanle signal in fluorescence excited by 647.1 and 676.4 nm Kr+-laser lines. The partial contribution gAb due to weak A∼b interaction was extracted from measured g factors for vA, J levels with vA between 8 and 29. The electronic part of the spin–orbit (SO) interaction matrix element Heso = 5.86± 0.20 cm-1 was determined by deperturbation fitting of gAb values. Possible error sources in A 1Σu+ state g-factor treatment due to imperfection in the physical model employed, inaccuracy of existing set of b 3Πu state molecular constants and nonlinear magnetic field effects were analyzed. [ABSTRACT FROM AUTHOR]

Values and signs of Landè factors (g) have been measured for four rovibronic levels of the A 1Σ+u state of the Na2 molecule. Because of a very small product gτ∼10-12 s, the level crossing signal of a dispersion shape was employed using circular light polarization and mutually orthogonal excitation, observation of laser induced fluorescence, and external magnetic field directions. The effects of the b 3Πu, B 1Πu, and a 3Σ+u states on the g factors of the Na2(A 1Σ+u), as well as their dependence on vibrational and rotational quantum numbers, have been theoretically analyzed. An analytical connection has been found between the constants of Λ doubling (q) and Landè factors of the interacting singlet states. Simple expressions have been found for estimating the effects of distant electronic states on q and the g factors without summing over bounded and integrating over continuum levels of the perturbing state. [ABSTRACT FROM AUTHOR]