Inelastic collisions between excited atoms and molecules; Sensitized fluorescence and quenching in mixtures of potassium and cesium with nitrogen, hydrogen, deuterium hydride and deuterium.
D. A. McGillis
2 2 2 2 P ^2 ------P3/2 mixin8 and Pj -----* Si / 2 quenchin8 in potassium and cesium vapors, induced by c o llis io n s with N2> H2, HD and D2, were studied using techniques of se n sitiz e d fluorescence.The m ixtures of a lk a li vapors w ith the various gases, in which the a lk a li vapor pressure was kept low to avoid ra d ia tio n trapping, were irr a d ia te d w ith one component of the appropriate resonance doublet.The fluorescence which contained both components of the doublet, was monitored a t rig h t angles to the d ire c tio n of e x c ita tio n .The measurements of the re la tiv e in te n s itie s of the fluorescent components yielded the to ta l in e la s tic 2 2 2 2 2 cross sections for P mixing, Q12( Pl /2 > P3/2 ^' Q21^ *1/2* P3/2 ^' and quenching, Q10^ P1/2 * S1/2^' Q20^ P3/2 * Sl/2^* In the case of potassium the quenching cross sections for N^, H2> HD and D2 were: Q10 = 35, 7, 11, 2 (£)2 and Q2Q = 39, 4, 14, 1 (£ )2, re sp e c tiv e ly .For the cesium resonance s ta te s the corresponding quenching cross sections O o were: Q10 = 62> 7' 4> 8 ^ and ^20 = 10° ' 5> 3> 7 ^ ' r e s Pe c tiv e ly • The potassium -N2, H2, HD and D2 mixing cross sections were found to be: Q12 = " '7> 75' 6' 74,° ' 72*2 and Q21 = 66*°' 53,2> 50,4, 48,7 re sp e c tiv e ly , only s lig h tly larg e r than the corresponding potassium -inert gas cross se ctio n s.The cesium -N2, H2, HD and D2 mixing cross sections were: Q = 4.7, 6.7, 4.8, 4.2 (£)2 and Q21 = 25.2, 43.8, 32.1, 27.8 (£ )2, resp e c tiv e ly , five orders of magnitude larg er than the cesium -inert gas mixing cross sectio n s. iii R ep ro d u ced with p erm ission o f th e copyright ow ner.Further reproduction prohibited w ithout perm ission.The quenching r e s u lts are c o n sisten t w ith the interm ediate complex th eo ries of quenching in which energy matching between the 2 atomic and m olecular s ta te s is of no importance.The P mixing cross sections do, however, exhibit a marked dependence on the ro ta tio n a l s tru c tu re of the c o llid in g m olecules.The r e s u lts are discussed in terms of induced ro ta tio n a l tra n s itio n s on the basis of which the cross sections ^21^ ^or m^x:'-n8 cesi-uni induced by ortho and para hydrogen are c a lcu lated .
•Jan 1, 1974•0 citations