Publication Date:
2016-07-14
Description:
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 ( f 00 = 0.9988 and f 11 = 0.9970) and branching ratios ( R 00 = 0.9965, R 01 = 2.85 × 10 −3 , R 02 = 6.35 × 10 −4 , and R 03 = 2.05 × 10 −6 ) for the A 1 Π 1 ( ν ′ = 0 ) → X 1 Σ 0 + + ( ν ″ = 0 ) transition are determined. A sufficiently radiative lifetime τ ( A 1 Π 1 ) = 4.99 ns is predicted for rapid laser cooling. The proposed cooling wavelength is deep in the ultraviolet region at λ 00 = 261.75 nm. Total emission rates for the a 3 Π 0 + → X 1 Σ 0 + + , a 3 Π 1 → X 1 Σ 0 + + , A 1 Π 1 → a 3 Π 0 + , and A 1 Π 1 → a 3 Π 1 transitions are particularly small (∼10 s −1 –650 s −1 ). The calculated vibrational branching loss ratio to the intermediate a 3 Π 0 + and a 3 Π 1 states can be negligible. The results imply the probability of laser cooling AlCl molecule with three-electronic-level.
Print ISSN:
0021-9606
Electronic ISSN:
1089-7690
Topics:
Chemistry and Pharmacology
,
Physics
