title: Laser cooling of the AlCl molecule with a three-electronic-level theoretical model.
abstract: Feasibility of laser-cooling AlCl molecule is investigated using ab initio quantum chemistry. Potential energy curves, permanent dipole moments, and transition dipole moments for the X(1)Σ(+), a(3)Π, and A(1)Π states are studied based on multi-reference configuration interaction plus Davidson corrections (MRCI+Q) method with ACVQZ basis set, spin-orbit coupling effects are considered at the MRCI+Q level. Highly diagonally distributed Franck-Condon factors (f00 = 0.9988 and f11 = 0.9970) and branching ratios (R00 = 0.9965, R01 = 2.85 × 10(-3), R02 = 6.35 × 10(-4), and R03 = 2.05 × 10(-6)) for the A(1)Π1(ν(')=0)→X(1)Σ0(+) (+)(ν(″)=0) transition are determined. A sufficiently radiative lifetime τ (A(1)Π1) = 4.99 ns is predicted for rapid laser cooling. The proposed cooling wavelength is deep in the ultraviolet region at λ00 = 261.75 nm. Total emission rates for the a(3)Π0(+) →X(1)Σ0(+) (+), a(3)Π1→X(1)Σ0(+) (+), A(1)Π1 → a(3)Π0(+) , and A(1)Π1 → a(3)Π1 transitions are particularly small (∼10 s(-1)-650 s(-1)). The calculated vibrational branching loss ratio to the intermediate a(3)Π0(+) and a(3)Π1 states can be negligible. The results imply the probability of laser cooling AlCl molecule with three-electronic-level.
authors.affiliation: Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin 644007, China.
authors.forename: Mingjie
authors.initials: M
authors.lastname: Wan
authors.affiliation: Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin 644007, China.
authors.forename: Di
authors.initials: D
authors.lastname: Yuan
authors.affiliation: Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin 644007, China.
authors.forename: Chengguo
authors.initials: C
authors.lastname: Jin
authors.affiliation: Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin 644007, China.
authors.forename: Fanhou
authors.initials: F
authors.lastname: Wang
authors.affiliation: Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin 644007, China.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Yang
authors.affiliation: College of Optoelectronic Technology, Chengdu University of Information Technology, Chengdu 610225, China.
authors.forename: You
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Computational Physics Key Laboratory of Sichuan Province, Yibin University, Yibin 644007, China.
authors.forename: Juxiang
authors.initials: J
authors.lastname: Shao