Photoassociation spectra and the validity of the dipole approximation for weakly bound dimers
- School of Engineering and Physical Sciences, James Cook University, Townsville, 4811 (Australia)
Photoassociation (PA) of ultracold metastable helium to the 2s2p manifold is theoretically investigated using a nonperturbative close-coupled treatment in which the laser coupling is evaluated without assuming the dipole approximation. The results are compared with our previous study [D. G. Cocks and I. B. Whittingham, Phys. Rev. A 80, 023417 (2009)], which makes use of the dipole approximation. The approximation is found to strongly affect the PA spectra because the photoassociated levels are weakly bound, and a similar impact is predicted to occur in other systems of a weakly bound nature. The inclusion of the approximation does not affect the resonance positions or widths; however, significant differences are observed in the background of the spectra and the maximum laser intensity at which resonances are discernible. Couplings not satisfying the dipole selection rule |J-1|{<=}J{sup '{<=}}|J+1| do not lead to observable resonances.
- OSTI ID:
- 21408440
- Journal Information:
- Physical Review. A, Vol. 81, Issue 3; Other Information: DOI: 10.1103/PhysRevA.81.033406; (c) 2010 The American Physical Society; ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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