# arc.divalent_atom_functions.DivalentAtom.getTransitionRate#

DivalentAtom.getTransitionRate(n1, l1, j1, n2, l2, j2, temperature=0.0, s=0.5)#

Transition rate due to coupling to vacuum modes (black body included)

Calculates transition rate from the first given state to the second given state $$|n_1,l_1,j_1\rangle \rightarrow |n_2,j_2,j_2\rangle$$ at given temperature due to interaction with the vacuum field. For zero temperature this returns Einstein A coefficient. For details of calculation see Ref. 1 and Ref. 2. See Black-body induced population transfer example snippet.

Parameters
• n1 (int) – principal quantum number

• l1 (int) – orbital angular momentum

• j1 (float) – total angular momentum

• n2 (int) – principal quantum number

• l2 (int) – orbital angular momentum

• j2 (float) – total angular momentum

• [temperature] (float) – temperature in K

• s (float) – optional, total spin angular momentum of state. By default 0.5 for Alkali atoms.

Returns

transition rate in s $${}^{-1}$$ (SI)

Return type

float

References

1

C. E. Theodosiou, PRA 30, 2881 (1984) https://doi.org/10.1103/PhysRevA.30.2881

2

I. I. Beterov, I. I. Ryabtsev, D. B. Tretyakov, and V. M. Entin, PRA 79, 052504 (2009) https://doi.org/10.1103/PhysRevA.79.052504