Direct laser cooling the NH molecule with the pseudo-closed loop triplet-triplet transition including intervening electronic states

Excellent Ultracold Molecular Candidates From Group VA Hydrides: Whether Do Nearby Electronic States Interfere?

“…For the four Λ-S states of NH, the energy difference between the four Λ-S states and the corresponding Ω states is less than 1 cm −1 . While the SO splitting values of the , and states are 34.04, 34.22 and 0.17 cm −1 , respectively, which are in excellent accordance with the computational values (the splitting values of the and states are 34.06 and 34.00 cm −1 , respectively) ( Yan et al, 2021 ). In Table 4 , the energy difference between the four Λ-S states ( , , and ) and the corresponding Ω states of PH is less than 6 cm −1 , whereas the SO splitting values of the , and states are 100.32, 102.83 and 1.16 cm −1 , respectively.…”

“…So far, there have not been theoretical investigations reported on laser cooling of PH to the best of our knowledge. Very recently, the → transition of NH has been used to establish a laser cooling scheme based on the ab initio calculation by Yan et al (2021) , however, the spin-orbit coupling (SOC) effects on the PECs and vibrational structures were not considered, and the influences of higher electronic states and the spin-orbit splitting of the state were not studied. In the present work, by means of highly accurate ab initio and dynamical calculations with the SOC effects included, two excellent ultracold molecular candidates from group VA hydrides are identified, which satisfy all known criteria of molecular laser cooling.…”

Uncertainty of High Temperature Heat Capacities: The Case Study of the NH Radical

“…Also partition function calculated from experimental energy levels of the ground electronic states is given (SUM EXP g). The energy levels were studied most recently in ref but only for low temperature applications.…”

Spectroscopic properties and laser cooling feasibility with the X1∏21/2↔X2∏23/2 transition for the PbX (X = F, Cl, Br, and I) molecules

“…Theoretical investigations on laser cooling of diatomic molecules have also attracted the interest of many researchers. For example, the laser cooling optical schemes of BeF [17], ScO [18], CuH [19], AuH [20], and NH [21] were proposed. Moreover, Li et al [22] assessed the direct laser cooling feasibility of XH (X = Si, Ge, Sn, and Pb) and CS molecules, and found that SiH and CS molecules are promising for laser cooling candidates.…”

“…For example, for BeF [17], LiRb [30], BH + [31], and BH − [31] molecules, the |ΔR e | for pseudo-closed transitions are 0.035, 0.085, 0.042, and 0.038 Å, the corresponding FCFs of the main transitions are 0.897, 0.872, 0.943, and 0.942, respectively. Yan et al [21] calculated the R e s for the X 3 Σ − and 3 Π 1 states of NH molecule are 1.0363 Å and 1.0364 Å, respectively, and constructed the optical scheme based on the 0.99972 of FCF for the X 3 Σ − (ν″ = 0) ↔ Π 1/2 → B 2 Σ 1/2 transition, the radiative lifetime of the B 2 Σ 1/2 state, and the spectroscopic constants for the B, D, E, and F states were determined for PbF by McRaven et al [49,50]. The Franck-Condon factors of B 2 Σ + ↔ X 1 2 Π 1/2 transition PbF were calculated by Chen et al [33] in 2022.…”