Laser spectroscopy of perturbed levels in N2(Bthinsp;3Pgr;g,v=10) and the first experimental determination of the N2(Arsquo;thinsp;5Sgr;+g) term energy

摘要

Using both a pulsed and a narrowhyphen;band cw dye laser, laserhyphen;induced fluorescence excitation spectra of N2(B,v=10) were observed on the N2(Bthinsp;3Pgr;glarr;Athinsp;3Sgr;+u) transition from the metastable N2(A) component of a molecular beam. Lifetime measurements were made for some of theB,v=10 rotational/fine structure levels, including one which was recently shown to exhibit very specific kinetic effects due to a perturbation by the N2(Arsquo;thinsp;5Sgr;+g) state lsqb;Ch. Ottinger, L. G. Smirnova and A. F. Vilesov, J. Chem. Phys.100, 4848 (1994)rsqb;. The perturbation manifested itself in the present work by a significantly longer lifetime of the3Pgr;e2(12) level relative to otherB,10 levels, as well as by line shifts. The S/O interaction matrix element is obtained to be 0.35 cmminus;1. From the required very close accidental coincidence between wellhyphen;identified levels in theBandArsquo;states the term energy of the latter could be precisely determined asTe(Arsquo;thinsp;5Sgr;+g)=75thinsp;990.0 cmminus;1. This is the first measurement of this value, and the result is bartil;440 cmminus;1lower than was predicted byabinitiocalculations. thinsp;