High-Resolution Rovibronic Cross Sections of the MgH+ Molecular Cation.

The high-resolution rovibronic line lists of the MgH+ molecular cation are presented in our work. The potential energy curves are calculated by the method of multireference configuration interaction and Davidson correction (MRCI+Q) with the spin-orbit coupling (SOC) effect. Spectroscopy constants are fitted and the results are in good agreement with experiments, ensuring the accuracy of the electronic structure. On account of potential energy curves and transition dipole moments, the Franck-Condon factors and Einstein coefficients of transition are obtained. These calculations are used to obtain an accurate partition functions and line lists for molecules. Using the partition functions and line lists, the absorption cross-sections under different temperatures and pressures were simulated. Our work could provide some theoretical insights into solar and cold planet spectrum.

The carrier mobility of monolayer and bulk GaS: from first-principles calculations.

Metal chalcogenides have become popular materials for next-generation electronic devices due to their wide band gap and excellent transport properties. Specifically, two-dimensional metal chalcogenides also have outstanding physical properties. For electronic devices, the carrier mobility is a key parameter because it affects the material conductivity and the response time. As a member of metal chalcogenides, GaS has attracted the attention of scholars. In this work, by using first principles calculations and the Wannier function interpolation, the electronic and phonon properties, the electron-phonon interaction, the scattering rate, and the carrier mobility of monolayer and bulk GaS are systematically studied. The results show that GaS is a semiconductor and both monolayer and bulk GaS are dynamically stable. The LO phonon modes at long wavelengths strongly affect the carrier migration in GaS. We give the carrier mobility of monolayer and bulk GaS as a function of temperature (100 < K < 500). In addition, we compare the carrier mobility of GaS with several other metal chalcogenides (monolayer and bulk InSe, monolayer GeS, and monolayer GeSe) at 300 K. The results show that an increase in temperature leads to a decrease in the carrier mobility and the electron (hole) mobility of monolayer and bulk GaS is 10.85 cm2 V-1 s-1 (0.22 cm2 V-1 s-1) and 1229.79 cm2 V-1 s-1 (9.28 cm2 V-1 s-1), respectively. By comparing with the carrier mobility of other chalcogenides, we can find that the electron mobility of bulk GaS is the highest, which indicates that bulk GaS has high application potential.

Spectroscopic Properties and Spin-Orbit Coupling of Electronic Excited States of GeCl.

The electronic structure and spectroscopic properties of GeCl+ are studied by high-level ab initio calculations by considering spin-orbit coupling (SOC). The potential energy curves (PECs) and spectroscopic constants of 12 Λ-S states and 23 Ω states are calculated using the multi-reference configuration interaction plus Davidson correction method (MRCI + Q), which are in good agreement with the experiment. Based on the calculated SO matrix and the PECs of the Ω states, the interaction between the d3Π state and other states caused by the SOC and the double-potential well structure caused by the avoided crossing rule and the properties of transitions d3Π0+-X1Σ+0+, d3Π1-X1Σ+0+, and a3Σ+1-X1Σ+0+ are studied. Our results indicate that the previously observed spectra of GeCl+ in the 290-325 nm range should be assigned as the a3Σ+1-X1Σ+0+ transition. Moreover, the predissociation behavior of the d3Π state between the vibrational levels v' = 1 and v' = 10 is discussed, and the radiative lifetimes of transitions d3Π0+-X1Σ+0+ and d3Π1-X1Σ+0+ are evaluated on the order of microseconds, while a3Σ+1-X1Σ+0+ is on the order of milliseconds. We estimate that the strongest bands of a3Σ+1-X1Σ+0+ are the 0-16, 0-17, and 0-18 bands. This study will promote our understanding of the detailed electronic structure and spectra of the GeCl+ radical cation.

Spectroscopy and rovibrational cooling of AuF and its cation.

The feasibility of laser cooling of AuF molecule and its cation are investigated from vibrational and rotational perspectives. The spectroscopy of AuF molecule and AuF+ molecular cation are obtained by the method of multireference configuration interaction plus Davidson correction (MRCI + Q) and spin-orbit coupling (SOC) effect. On account of the accurate molecular spectroscopy and the transition dipole moment, the Franck-Condon factors and radiative lifetimes of AuF molecule and AuF+ molecular cation are calculated. Comparing the criterias of laser cooling candidate molecules, the AuF is an excellent candidate for laser cooling and while AuF+ is not sutable. The b3Π0+ ↔ Χ1Σ+0+ transition of AuF is selected for laser cooling and an optical cycling scheme is proposed. The scheme possesses highly diagonally Franck-Condon factors and the scattered photons achieve âˆ¼ 104. Furthermore, the rotational transition analysis is also included in our work and found that its Franck Condon factors and Einstein coefficients are undistorted. Our work could provide theoretical support and accelerate the laser cooling of AuF molecules in experiments.

The vibrational and hyperfine spectroscopy toward laser cooling 87Sr35Cl.

We theoretically investigate the possibility of laser cooling 87Sr35Cl molecule in accordance with vibrational and hyperfine spectroscopy. The potential energy curves and dipole moment of the X2Σ+1/2, A2Π1/2,3/2 and B2Σ+ states are calculated using ab initio method and the spectroscopic parameters are in good agreement with the experimental data. On account of the accurate potential energy curves and the transition dipole moment, the Franck - Condon factors and radiative lifetimes are predicted. Comparing the conditions of laser cooling candidate molecules, the A2Π 1/2 â†” X2Σ+1/2 transition is selected as the laser cooling cycle system. In order to obtain an approximately closed cooling cycle system, we employed matrix element algorithm to calculated the hyperfine spectroscopy and branching ratios of the 87Sr35Cl molecule. Furthermore, an electro-optical modulator (EOM) is designed including six hyperfine levels of the ground state X2Σ+1/2 (v = 0, N = 1).

Ab initio investigation on the low-lying electronic states of thallium bromide.

Thirteen Λ-S states of TlBr molecule are calculated by the method of multireference configuration interaction (MRCI) plus Davidson correction (+Q), and the spectroscopic constants of these states are fitted. The dipole moment of thirteen Λ-S states are also included and analyzed in this calculation. Two bound states split into five Ω states with the SOC effect. The interaction between the molecular configurations of TlBr is analyzed with spin orbit coupling. Considering the forbidden transition, transition dipole moment with SOC effect is considered. On account of the accurate potential energy curves and the transition dipole moment, the Franck-Condon factors and radiative lifetime of the a3Π0+ ↔ Χ1Σ0++ transition are calculated. The feasibility of laser cooling of TlBr molecule is analyzed by comparing with the thallium compounds and the bromides of the group-IIIA.