Experimental studies of the NaCs 53Π and 1(<i>a</i>)3Σ+ states

Ashman, Seth; McGeehan, Brett; Wolfe, Christopher; Faust, Carl; Richter, K.; Jones, Joshua; Hickman, A. P.; Huennekens, J.

doi:10.1063/1.3689388

Cited by 14 publications

(7 citation statements)

References 110 publications

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“…Similar situations arise in other alkali diatomic molecules, for example in recent work on LiCs, where RKR-based energy level differences were sometimes of the order of 5 cm −1 [91]. Discrepancies of this magnitude are found in other applications of RKR potentials to perturbed states [39,92]. We conclude that the levels that appear to be only minimally perturbed are in fact shifted by spin-orbit coupling effects to the extent of 0.1 to 2.0 cm −1 .…”

Section: Comparison With Previous Resultssupporting

confidence: 55%

Experimental and theoretical studies of the coupledA1Σ+andbΠ<

et al. 2015

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We report an extensive series of transitions (including collisional transfer lines) from pure and mixed levels of the NaK A 1 Σ + and b 3 Π states to the X 1 Σ + state, observed in Lyon using Fourier transform spectroscopy. We then combine these data with previously reported data on these states from emission from the B 1 Π and C 1 Σ + states and from mutually perturbed levels of the D 1 Π and d 3 Π states. We obtain 2758 distinct term values: the full data set includes 11624 term values, with many multiple determinations from transitions over a range of vibrational and rotational levels. The data are analyzed by fitting to potentials of the "Hannover" form (Samuelis et al., Phys. Rev. A 63, 012710 (2000)) plus spin-orbit (SO) functions in a simple Morse form, yielding an rms residual of approximately 0.029 cm −1. The empirical SO functions agree well with their ab initio counterparts obtained from electronic structure calculations based on non-empirical effective core potentials. From level energies of the A − b complex calculated from the fitted potentials and SO functions, we identify reasonable candidates for transitions between Feshbach resonance states and mixed singlettriplet gateway levels of the A 1 Σ + − b 3 Π manifold leading either to v=0 levels of the X state, or to mixed singlet-triplet levels at higher energies that can be used for perturbation-facilitated double resonance experiments.

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Section: Comparison With Previous Resultssupporting

confidence: 55%

Experimental and theoretical studies of the coupledA1Σ+andbΠ<

et al. 2015

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“…In contrast to the present results for NaK, and the earlier work on 6 Li 7 Li, 90 preliminary work in our laboratory on collisions of NaCs molecules with argon atoms shows no such propensity. 93 This follows from the argument that NaCs is "more heteronuclear" implying that the anisotropies in the potential energy surface are more significant. However, both McCurdy and Miller 91 and Maricq 92 point out that the situation is more complicated than this simple view, with calculations showing propensities for J = odd transitions for certain choices of the anisotropy parameters (coefficients of the even and odd Legendre polynomial terms used to describe the interaction potential).…”

Section: Discussionmentioning

confidence: 99%

Collisional transfer of population and orientation in NaK

Wolfe

Ashman

Bai

et al. 2011

The Journal of Chemical Physics

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Collisional satellite lines with |ΔJ| ≤ 58 have been identified in recent polarization spectroscopy V-type optical-optical double resonance (OODR) excitation spectra of the Rb(2) molecule [H. Salami et al., Phys. Rev. A 80, 022515 (2009)]. Observation of these satellite lines clearly requires a transfer of population from the rotational level directly excited by the pump laser to a neighboring level in a collision of the molecule with an atomic perturber. However to be observed in polarization spectroscopy, the collision must also partially preserve the angular momentum orientation, which is at least somewhat surprising given the extremely large values of ΔJ that were observed. In the present work, we used the two-step OODR fluorescence and polarization spectroscopy techniques to obtain quantitative information on the transfer of population and orientation in rotationally inelastic collisions of the NaK molecules prepared in the 2(A)(1)Σ(+)(v' = 16, J' = 30) rovibrational level with argon and potassium perturbers. A rate equation model was used to study the intensities of these satellite lines as a function of argon pressure and heat pipe oven temperature, in order to separate the collisional effects of argon and potassium atoms. Using a fit of this rate equation model to the data, we found that collisions of NaK molecules with potassium atoms are more likely to transfer population and destroy orientation than collisions with argon atoms. Collisions with argon atoms show a strong propensity for population transfer with ΔJ = even. Conversely, collisions with potassium atoms do not show this ΔJ = even propensity, but do show a propensity for ΔJ = positive compared to ΔJ = negative, for this particular initial state. The density matrix equations of motion have also been solved numerically in order to test the approximations used in the rate equation model and to calculate fluorescence and polarization spectroscopy line shapes. In addition, we have measured rate coefficients for broadening of NaK 3(1)Π ← 2(A)(1)Σ(+)spectral lines due to collisions with argon and potassium atoms. Additional broadening, due to velocity changes occurring in rotationally inelastic collisions, has also been observed.

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“…Understanding the underlying mechanisms of atom-molecule collisional processes is of fundamental importance for many research areas including chemical reactivity, ultracold atoms and molecules, and astrophysics of the interstellar medium. In addition, collision-induced satellite lines can be used to expand the size of datasets in spectroscopic studies of molecules [1][2][3]. In general, molecules are not spherically symmetric objects and as a result most collisional processes involving them depend strongly on the relative alignment of the colliding partners.…”

Section: Introductionmentioning

confidence: 99%

The effect of collisions on the rotational angular momentum of diatomic molecules studied using polarized light

Arndt

Huennekens

Packard

et al. 2020

The Journal of Chemical Physics

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We report results of an experimental study of the changes in the alignment of the rotational angular momentum of diatomic molecules during elastic collisions. The experiment involved collisions of diatomic lithium molecules in the 1 u A +  excited electronic state with noble gas atoms (helium and argon) in a thermal gas phase sample. Polarized light for excitation was combined with detection of polarization-specific fluorescence in order to achieve magnetic sublevel state selectivity. We also report results for rotationally inelastic collisions of Li2 in the lowest lying rotational levels of the

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Experimental studies of the NaCs 53Π and 1(a)3Σ+ states

Cited by 14 publications

References 110 publications

Experimental and theoretical studies of the coupledA1Σ+andbΠ<

Experimental and theoretical studies of the coupledA1Σ+andbΠ<

Collisional transfer of population and orientation in NaK

The effect of collisions on the rotational angular momentum of diatomic molecules studied using polarized light

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