LINE INTENSITIES AND MOLECULAR OPACITIES OF THE FeH F ^4Delta~i-X ^4Delta~i TRANSITION

Order α6mc2 corrections to the fine structure splitting of the deepest triplet P state (23P0,1,2) of the He4 atom have been investigated. The investigation is based on the covariant Bethe-Salpeter equation including external potential to take account of the nuclear Coulomb field. All order α6mc2 corrections which arise from Feynman diagrams involving the exchange of one, two, and three photons, as well as radiative corrections to the electron magnetic moment have been found. The results are presented in a form suitable for computerized numerical evaluation.

Quantum-Electrodynamical Corrections to the Fine Structure of Helium.

Optical cycling, a continuous photon scattering off atoms or molecules, plays a central role in the quantum information science. While optical cycling has been experimentally achieved for many neutral species, few molecular ions have been investigated. We present a systematic theoretical search for diatomic molecular ions suitable for optical cycling using equation-of-motion coupled-cluster methods. Inspired by the electronic structure patterns of laser-cooled neutral molecules, we establish the design principles for molecular ions and explore various possible cationic molecular frameworks. The results show that finding a perfect molecular ion for optical cycling is challenging, yet possible. Among various possible diatomic molecules we suggest several candidates, which require further attention from both theory and experiment: YF+, SiO+, PN+, SiBr+, and BO+.

In search of molecular ions for optical cycling: a difficult road.

Improved optical control of molecular quantum states promises new applications including chemistry in the quantum regime, precision tests of fundamental physics, and quantum information processing. While much work has sought to prepare ground state molecules, excited states are also of interest. We demonstrate a broadband optical approach to pump trapped SiO$^+$ molecules into pure super rotor ensembles maintained for many minutes. Super rotor ensembles pumped up to rotational state $N=67$, corresponding to the peak of a 9400 K distribution, had a narrow $N$ spread comparable to that of a few-kelvin sample, and were used for spectroscopy of the previously unobserved C$^2\Pi$ state. Significant centrifugal distortion of super rotors pumped up to $N=230$ allowed probing electronic structure of SiO$^+$ stretched far from its equilibrium bond length.

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Precisely Spun Super Rotors

This research article investigates the effects of magnetic and Aharanov-Bohm (AB) fields on the thermo-magnetic and transport properties and magneto-caloric effect (MCE) of Lithium Hydride (LiH) modelled by the Varshni potential. So, the Schrödinger equation in 2D is solved under the influence of external fields and Varshni potential using the functional analysis approach (FAA) to obtain the energy equation and wave function, respectively. The accessible energy levels are summed to obtain the partition function, which is used to obtain the aforementioned properties. The influences of the magnetic and AB fields on the above-mentioned properties have been examined over a broad temperature region. The susceptibility has only positive values in different scenarios analysed, which implies paramagnetism. The temperature dependence of the magnetic entropy (magneto-caloric effect) changes shows a decreasing tendency. This research could find applications in molecular physics and inspire discussions and studies on MCE for several diatomic molecules. GRAPHICAL ABSTRACT

The magnetocaloric effect, thermo-magnetic and transport properties of LiH diatomic molecule

Molecular Opacity Calculations for Lithium Hydride at Low Temperature

SiO+ and SiO, which play vital roles in astrophysics and astrochemistry, have long attracted considerable attention. However, accurate information about excited states of SiO+ is still limited. In this work, the structures of 14Λ–S states and 30 Ω states of SiO+ are computed with explicitly correlated configuration interaction method. On the basis of the calculated potential energy curves of those Λ–S states and Ω states, the spectroscopic constants of bound states are evaluated, which are in good agreement with the latest experimental results. The predissociation mechanism of state is illuminated with the aid of spin–orbit coupling matrix elements. On the basis of the calculated potential energy curves and transition dipole moments, the radiative lifetime for each of low-lying vibrational states and is estimated. The laser cooling scheme of SiO+ is proposed by employing transition. Finally, the vertical ionization energy values from SiO ( to ionic states: SiO+, , , and are calculated, which agree well with experimental measurements.

Gui-Ying Liang

Papers

Molecular Opacity Calculations for Lithium Hydride at Low Temperature

Explicitly correlated configuration interaction investigation on low-lying states of SiO+ and SiO*

Molecule opacities of ${{\rm{X}}}^{2}{{\rm{\Sigma }}}^{+}$, ${{\rm{A}}}^{2}{\rm{\Pi }}$, and ${{\rm{B}}}^{2}{{\rm{\Sigma }}}^{+}$ states of CS+