Theoretical Calculation of Caq+ (q = 0, 1, 2) Interacting with a Krypton Atom: Electronic Structure and Vibrational Spectra Association

The effect of spin-orbit coupling on molecular properties: Potential energy curve, transition dipole moment and laser cooling scheme of NH

Ab initio study on the low-lying excited states of gas-phase PH+ cation including spin–orbit coupling

BH+ cation is one of the candidates for laser cooling. The potential energy curves (PECs) for nine electronic states (X2+, A2, B2+, a4, b4+, 32+, 22, 32, 42+) relating to the B+(1Sg)+H(2Sg), B+(3Pu)+H(2Sg), B(2Pu)+H+(1Sg), and B+(1Pu)+H(2Sg) dissociation channels of BH+ cation are obtained using highly accurate multi-reference configuration interaction (MRCI) plus Davidson correction. All-electron basis sets AV5Z-DK for H and ACV5Z-DK for B are used in PEC calculations for the -i-S states of BH+ cation, respectively. In complete active space self-consistent field (CASSCF) calculation, H(1s2s2p3s3p) and B(2s2p) are chosen as active orbitals, B(1s) is the closed shell; in the MRCI calculation, the core-valence (CV) correction is considered, i.e., B(1s) shell is used for CV correlation. Spin-orbit coupling effects are considered with Breit-Pauli operators. Spectroscopic constants are fitted using the Murrell-Sorbie function. Spectroscopic constants for the X2+, A2, and B2+ states are in excellent agreement with the available experimental data; spectroscopic constants for the b4+, 32+, 32, and 42+ states are reported. Two potential wells for the 32 and 42+ states are found. The maximum fitting error of all electronic states is only 3.407 cm-1. In addition, PECs for the A2 and B2+ states are crossed at about 2.7 . Then, the transition dipole moments (TDMs) for the A2 X2+, B2+X2+, 32+X2+, B2+ A2, 32 X2+ and b4+ a4 transitions are also obtained. The strength for the B2+ A2 transition is very weak. Based on the accurate PECs and TDMs, the Franck-Condon factors and spontaneous radiative lifetimes are calculated. A strongly diagonal Franck-Condon factor (f00) for the A2X2+ transition is obtained, which equals 0.9414. Spontaneous radiative lifetime for the A2 and B2+ states is also predicted. i.e., (A2)=239.2 ns and (B2+)=431.2 ns. When SOC effect is considered, the A21/2 and B21/2+ states avoid crossing in the Franck-Condon region (R is about 2.7 ). Calculated f00 for the A21/2 X21/2+ transition is 0.9430; spontaneous radiative lifetime for the A21/2 is 239.0 ns. Our calculated results indicate that the influence for laser cooling BH+ cation via the crossing between B2+ and A2 states can be ignored.

The potential energy curves (PECs) associated with the lowest four dissociation limits, i.e., Zn(1Sg)+H(2Sg), Zn(3Pu)+H(2Sg), Zn+(2Sg)+H-(1Sg) and Zn(1Pu)+H(2Sg), are calculated by using a high-level configuration interaction method. The Davidson correction, scalar relativistic effect and spin-orbit coupling effect are taken into account in calculation. On the basis of our calculated PECs of -S and states, the spectroscopic constants including Te, e, ee, Be and Re are evaluated by numerical solution of one-dimensional Schrdinger equation. The computed spectroscopic constants are reasonably consistent with previous experimental results. The dipole moment curves of the 7 -S states are presented, and the influences of the variation of electronic configuration on the dipole moment and bonding property are discussed. The computational results reveal the ionic character of the C2+ state. The variation of -S component for state near the avoided crossing point is illuminated, which is used to explain the change of transition dipole moment (TDM) around the avoided crossing point. Based on the TDMs, Franck-Condon factors and the transition energies, the radiative lifetimes of v'=0-2 vibrational levels of (2)1/2, (3)1/2, (4)1/2 and (1)3/2 states are predicted, which accord well with the available experimental values.

MRCI study on transition dipole moments and transition probabilities of 18 low-lying states of CP+ cation

Configuration interaction investigation including spin–orbit coupling effect for electronic states of IBr and its cation

The hyperfine structure branching ratios and ab initio study on low-lying electronic states for 24Mg19F molecule

Theoretical study of spectroscopic constants and transition properties of silicon hydride cation

Using an ab initio approach based on nonempirical pseudopotentials for the Mg(2+) and Li(+) cores, Gaussian basis sets, effective core polarization potentials and full configuration interaction calculations, the adiabatic potential energy curves, the spectroscopic constants, the permanent and transition electric dipole moments of the several lowest electronic states of the alkali-alkaline earth ion MgLi(+) have been performed. These states dissociate into Mg(+)(3s and 3p) + Li (2s, 2p, 3s, 3p, 3d, 4s, 4p, and 4d) and Mg (3s(2), 3s3p, 3s4s, 3s3d, 3s4p, 3s5s, and 3s4d) + Li(+). The spectroscopic constants (Re, De, Te, ωe, ωexe, and Be) of the ground state and nearly 53 excited states of (1,3)Σ(+), (1,3)Π, and (1,3)Δ symmetries are derived. Most of them are computed for the first time. Moreover, several avoided crossings between the electronic states of (1,3)Σ(+), (1,3)Π symmetries are localized and analyzed. Their existence is related to the interaction between the potential energy curves and to the charge transfer process between the two ionic systems Mg(+)Li and MgLi(+). Furthermore, accurate adiabatic permanent and transition dipole moments for several transitions have been calculated for a large and dense grid of internuclear distances for the first 15 (1)Σ(+) electronic states. A linear behavior is observed in the permanent dipole moments for several electronic states. Additionally, the transition electric dipole moments between neighbor states have shown many peaks situated around the avoided crossing positions.

In this paper, we calculate the potential energy curves of 5 -S and 10 , which arise from the first two dissociation limits of the AlH+ cation. The calculations are done using the complete active space self-consistent field method, which combines with the valence internally contracted multireference configuration interaction plus the Davidson modification (icMRCI+Q) approach with the aug-cc-pV6Z basis set. To improve the reliability and accuracy of the potential energy curves, the core-valence correlation and scalar relativistic correction, as well as the extrapolation of potential energy to the complete basis set limit are taken into account. The spin-orbit coupling is computed using the state interaction approach with the Breit-Pauli Hamiltonian. Employing the potential energy curves obtained in this study, we evaluate the spectroscopic parameters and vibrational levels for the bound and quasi-bound 4 -S and 8 states. The computed spectroscopic constants of X2+ and A2 states are all in agreement with the available experimental data. Moreover, the present theoretical energy separations between each higher channel (Al+(3P0) + H(2S1/2), Al+(3P1) + H(2S1/2), and Al+(3P2) + H(2S1/2) and the lowest one (Al+(1S0) + H(2S1/2)) are in excellent agreement with the experimental values. The transition dipole moments are calculated using the valence internally contracted multireference configuration interaction approach with the aug-cc-pV6Z basis set for the 2(1/2) X21/2+ and A23/2X21/2+. Based on the obtained potential energy curves and transition dipole moments, highly diagonally distributed Franck-Condon factors (f00 and f11) and large vibrational branching ratios are determined for the 2(1/2)1st well (v'=0, 1) X21/2+ (v) and A23/2(v'=0,1)X21/2+(v) transitions; short spontaneous radiative lifetime and narrow radiative width for the 2(1/2)1st well (v'=0, 1) and A23/2 (v'=0, 1) are also predicted in this study, which are suitable for the rapid laser cooling of the AlH+ cation. The three required laser cooling wavelengths are all in the ultraviolet region, that is, 1) for the X21/2+(v) 2(1/2)1st well (v') transition:the main repumping laser 00=358.74 nm, two repumping lasers 10=379.27 nm and 21=374.86 nm; 2) for the X21/2+ (v) A23/2 (v') transition:the main repumping laser 00=357.43 nm, two repumping lasers 10=377.80 nm and 21=373.26 nm. In addition, the recoil temperature for the X21/2+ (v=0) 2(1/2)1st well (v'=0) and X21/2+ (v=0) A23/2 (v'=0) transitions are obtained. The results imply the feasibility of laser cooling of AlH+ cation. In addition, the spin-orbit coupling effect on the spectroscopic parameter, vibrational level, and laser cooling of AlH+ cation are evaluated.

Extensive theoretical study on the excited states of the PCl+ molecule including spin-orbit coupling

The adiabatic potential energy curves and the permanent and transition dipole moments of the low-lying electronic states of the NaLi molecule dissociating into Na(3s, 3p, 4s, 3d, 4p) + Li(2s, 2p, 3s, 3p, 3d) have been investigated. The molecular calculations are performed using an ab initio approach based on non-empirical pseudopotentials for Na+ and Li+ cores, parameterized l-dependent polarization potentials and full configuration interaction calculations through the CIPCI quantum chemistry package. The derived spectroscopic constants of the ground state and lower excited states are in good agreement with available experimental and theoretical works. However, the 7–101,3Σ+, 5–71Π, 2–63Π and 1–31,3Δ excited states are studied for the first time. The permanent dipole moment of NaLi has revealed both ionic characters relating to electron transfer and yielding Na+Li− and Na−Li+ arrangements. The transition dipole moment is used to evaluate the radiative lifetimes of the vibrational levels trapped in the 21Σ+ excited state for the first time. In addition to the bound–bound contribution, the bound-free term has been evaluated exactly using the Franck–Condon (FC) approximation and added to the total radiative lifetime.

Spin-orbit coupling effects in the spectroscopy and predissociation of the low-lying states of germanium monobromide

Spectroscopic Constants and Predissociation of the low-lying states in selenium dimer

High-level multireference configuration interaction plus Davidson correction (MRCI + Q) calculation method was employed to determine the potential energy curves (PECs) of 10 Λ-S states, which come from the first and second dissociation channels of the SbP molecule, as well as 34 Ω states considering the spin-orbit coupling (SOC) effect. By solving the Schrödinger equation for nuclear motion, spectroscopic constants for the ground state X1Σ+ and low-lying excited states were obtained and compared with experimental data. The excellent agreement indicates the reliability of our calculations. Additionally, the calculated spin-orbit (SO) matrix elements of the 13Π and 15Π states with other Λ-S states were analyzed, and the majority of the values in the Franck-Condon region exceed 200 cm-1, indicating strong interactions between these states. What's more, the joint effects of spin-orbit coupling and avoided crossing were discussed in detail, leading to the complex potential energy curves and double-well phenomena observed in the Ω states. Taking forbidden transitions into account, transition dipole moments with the SOC effect are considered. The Franck-Condon factors, Einstein coefficients, and radiative lifetimes for the 13Σ+1 ↔ X1Σ+0+ transition were obtained. Analysis indicates that direct laser cooling of SbP is inappropriate.