| Autor: |
Moore, Keith, Lane, Ian C |
| Rok vydání: |
2018 |
| Předmět: |
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| Druh dokumentu: |
Working Paper |
| DOI: |
10.1016/j.jqsrt.2018.03.003 |
| Popis: |
Tiny radiative losses below the 0.1% level can prove ruinous to the effective laser cooling of a molecule. In this paper the laser cooling of a hydride is studied with rovibronic detail using ab initio quantum chemistry in order to document the decays to all possible electronic states (not just the vibrational branching within a single electronic transition) and to identify the most populated final quantum states. The effect of spin-orbit and associated couplings on the properties of the lowest excited states of BaH are analysed in detail. The lifetimes of the A$^2{\Pi}_{1/2}$, H$^2{\Delta}_{3/2}$ and E$^2{\Pi}_{1/2}$ states are calculated (136 ns, 5.8 {\mu}s and 46 ns respectively) for the first time, while the theoretical value for B$^2{\Sigma}^+_{1/2}$ is in good agreement with experiments. Using a simple rate model the numbers of absorption-emission cycles possible for both one- and two-colour cooling on the competing electronic transitions are determined, and it is clearly demonstrated that the A$^2{\Pi}$ - X$^2{\Sigma}^+$ transition is superior to B$^2{\Sigma}^+$ - X$^2{\Sigma}^+$, where multiple tiny decay channels degrade its efficiency. Further possible improvements to the cooling method are proposed. |
| Databáze: |
arXiv |
| Externí odkaz: |
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