title: Direct measurement of the radiative lifetime of vibrationally excited OH radicals.
abstract: Neutral molecules, isolated in the gas phase, can be prepared in a long-lived excited state and stored in a trap. The long observation time afforded by the trap can then be exploited to measure the radiative lifetime of this state by monitoring the temporal decay of the population in the trap. This method is demonstrated here and used to benchmark the Einstein A coefficients in the Meinel system of OH. A pulsed beam of vibrationally excited OH radicals is Stark decelerated and loaded into an electrostatic quadrupole trap. The radiative lifetime of the upper Lamda-doublet component of the Chi2Pi3/2, v=1, J=3/2 level is determined as 59.0+/-2.0 ms, in good agreement with the calculated value of 58.0+/-1.0 ms.
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
authors.forename: Sebastiaan Y T
authors.initials: SY
authors.lastname: van de Meerakker
authors.forename: Nicolas
authors.initials: N
authors.lastname: Vanhaecke
authors.forename: Mark P J
authors.initials: MP
authors.lastname: van der Loo
authors.forename: Gerrit C
authors.initials: GC
authors.lastname: Groenenboom
authors.forename: Gerard
authors.initials: G
authors.lastname: Meijer