On the importance of an M2 depopulating channel for a KrII metastable state

• Published in: Physical review letters Vol. 93; no. 6; p. 063003
• Main Authors: Biémont, Emile, Derkatch, A., Lundin, P., Mannervik, S., Norlin, L. O., Rostohar, D., Royen, P., Palmeri, P., Schef, P.
• Format: Web Resource Journal Article
• Language: English
• Published: American Physical Soc 06-08-2004
• Subjects: Physical, chemical, mathematical & earth Sciences; Physics; Physique; Physique, chimie, mathématiques & sciences de la terre
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/PhysRevLett.93.063003

An experimental investigation of the radiative lifetime of the metastable 4s(2)4p(4)(P-3)4d D-4(7/2) level in Kr II shows an unusual situation regarding the importance of an M2 depopulation channel. While the first order M1 and E2 channels are expected to contribute in a dominant way to the decay, the experimental result, obtained using a laser probing technique on a stored ion beam, tau=0.57+/-0.03 s, is far too short to be due to these channels according to our relativistic multiconfiguration Dirac-Fock calculation. Only if second order contributions to the decay branches (including essentially the M2 contribution) are taken into account in the calculations could the unexpected short lifetime be explained.