Ths p ro p e rtie s o f newly developed potassium and rubidium s p e c tr a l lamps have been s y ste m a tic a lly in v e s tig a te d in r e l a t i o n to t h e i r o p eratin g parameters* A comparison was made w ith two com m e rc ia lly a v a ila b le lamps* manufactured by Osram and Varian Asso c i a te s !w ith re sp e c t to in te g ra te d in te n s ity * peak in te n s ity * h a lf width* and degree of s e lf -r e v e r s a l of th e resonance l i n e s .I t was found th a t the rad io freq u en cy sources* developed in t h i s laboratory* emit potassium and rubidium resonance lin e s o f s ig n if i c a n tl y h ig h e r peak in t e n s i t i e s and sm aller h alf-w id th s th an th o se produced by th e o th e r lamps.The degree o f s e lf -r e v e r s a l in th e resonance lin e s was a ls o found to be very much more advantageous.T ypical h a lf-w id th s of th e resonance lin e s of potassium and rubidium produced by the r a d io f r e quency source were found to be 0 .1 5 cm.~^ and 0 .j57cm.~^ r e s p e c tiv e ly , compared to th e corresponding widths o f 0 .J 4 cm."* and 1 .5 cm.'* 1
Ths p ro p e rtie s o f newly developed potassium and rubidium s p e c tr a l lamps have been s y ste m a tic a lly in v e s tig a te d in r e l a t i o n to t h e i r o p eratin g parameters* A comparison was made w ith two com m e rc ia lly a v a ila b le lamps* manufactured by Osram and Varian Asso c i a te s !w ith re sp e c t to in te g ra te d in te n s ity * peak in te n s ity * h a lf width* and degree of s e lf -r e v e r s a l of th e resonance l i n e s .I t was found th a t the rad io freq u en cy sources* developed in t h i s laboratory* emit potassium and rubidium resonance lin e s o f s ig n if i c a n tl y h ig h e r peak in t e n s i t i e s and sm aller h alf-w id th s th an th o se produced by th e o th e r lamps.The degree o f s e lf -r e v e r s a l in th e resonance lin e s was a ls o found to be very much more advantageous.T ypical h a lf-w id th s of th e resonance lin e s of potassium and rubidium produced by the r a d io f r e quency source were found to be 0 .1 5 cm.^ and 0 .j57cm.^ r e s p e c tiv e ly , compared to th e corresponding widths o f 0 .J 4 cm."* and 1 .5 cm.'* 1
The method of s e n s itiz e d flu o re sc e n c e was used to d e t e r mine cro ss s e c tio n s f o r th e v ario u s e x c i ta t io n t r a n s f e r p ro cesses 2 2 occuring in K -Rb vapour m ix tu res and f o r ** ^3 /2 ™i%ing and 2 2 2 ^1^2 ^1/ 2 ' ^3 /2 quenching in rubidium induced in c o l l i s i o n s w ith se v e ra l d iatom ic and polyatom ic m olecules in t h e i r ground s t a t e s .The a l k a l i vapour in th e flu o resce n ce c e l l , which was kept a t low p re s s u re s to avoid s e rio u s e f f e c t s o f r a d ia tio n im prisonm ent, was ir r a d i a te d by one component of th e a p p ro p ria te resonance d o u b le t.The r e s u ltin g flu o re s c e n c e , which c o n s is te d o f the w avelength component p re s e n t in th e e x c itin g li g h t (resonance flu o re sc e n c e ) and th o se components which aro se from th e em ission by atoms c o l l i s i o n a l l y p o pulated ( s e n s itiz e d flu o re s c e n c e ), was reso lv ed and observed a t r ig h t an g les to th e d ir e c tio n o f th e in c id e n t beam.Measurements of s e n s itiz e d -to -r e s o n a n c e flu o re s c e n t in t e n s ity r a t i o s in r e l a t i o n to rubidium vapour p re s s u re y ie ld e d the fo llo w in g cro ss s e c tio n s fo r e x c i ta t io n t r a n s f e r in K -Rb vapour m ix tu re s: ^1 2 ' ( ^^^1 /2 = 40 f , Qgg, (K4^P^yg ^ Rb$^P^yg) = 2 ?Q i^,(K 4^Pi/2 -, Rb$2p^yg) = 2 .7 Qg^,(K4^Pgyg -Rb^^P^y^) = 1,9 qJ_2(k4^Pi/2 -K4^P^yj = 260 f , and Q^'(KA^P^y^ -KA^P^y^) = 175 In m ix tu res o f rubidium w ith m olecular g a s e s , measurements o f the i n t e n s ity r a t i o s in r e l a t i o n to gas p re s s u re s gave the fo llo w in g c ro s s s e c tio n s fo r th e mixing and quenching c o l l i s i o n s .
A description is given of radio frequency light sources which produce potassium and rubidium resonance radiation of high intensity. The properties of the spectral lamps have been systematically investigated in relation to their operating parameters. The rf lamps emit resonance lines of much higher peak intensities, smaller halfwidths and smaller degrees of self-reversal than do commercially available lamps. Typical halfwidths of the resonance lines of potassium and rubidium produced by the rf sources were found to be 0.15 cm−1 and 0.37 cm−1, respectively, compared with the corresponding widths of 0.34 cm−1 and 1.5 cm−1, respectively, emitted by Osram spectral lamps operated at low currents.
in g the o n s e t of d is s ip a tio n at th e ro to n c r i t ic a l v e lo c ity in s u p e r flu id h e liu m .T h is is a c la s s ic a l , c o r r e s p o n d e n c e -p r in c ip le -lim it po in t of v iew and is q u ite an alo g o u s to th e c la s s ic a l d e s c r ip tio n that i s w idely a c c e p te d fo r u n d e rs ta n d in g the e m is s io n of photons by an e le c t r i c c h a rg e th a t m o v e s at a c o n s ta n t v e lo c ity g r e a t e r th a n the sp e e d of lig h t in a d ia le c tr ic m e d iu m .A fte r f i r s t d e riv in g a th e o ry f o r th e w ave e x c ita tio n s and b o u n d a ry -v a lu e p ro b le m s of the c o rre s p o n d e n c e p rin c ip le lim it fo r a co n d en se d -b o so n s y s te m , th is p a p e r show s th a t a w ave r a d i a tio n field f o r m s a ro u n d a fo re ig n body m o v in g th ro u g h the s u p e r fluid m e d iu m w hen the fo re ig n body m o v e s f a s t e r th an the m in im u m p h a se v e lo c ity , {w/k )m jn » w ave e x c ita tio n s in the m e d iu m .M o re o v e r, the sp a tia l d e p e n d e n c e of th is w ave fie ld and the lo s s of e n e rg y r a d ia tin g th ro u g h it a r e c a lc u la te d a s fu n ctio n s of the f r a c tio n a l in c r e a s e of the fo re ig n b o d y 's v e lo c ity above the th r e s h o ld v e lo c ity In s p ite of a p p ro x im a tio n s m a d e in th e c a lc u la tio n s , th e r e s u l t s in d ic a te th a t it is im p o s s ib le , e x p e r i m e n ta lly , to f o r c e an io n c o m p lex to m ove th ro u g h the s u p e rflu id c o m ponent o f h e liu m a t a v e lo c ity o b s e r v a b ly g r e a t e r th an th e ro to n c r i t i c a l v e lo c ity .ACKNOWLEDGMENTS I would lik e to thank P r o f e s s o r R. L. M ills fo r h is c o n trib u tio n s to m y g ra d u a te ed u catio n and fo r h is p e rc e p tiv e c o u n s e l w hile th is r e s e a r c h w a s b e in g c o n d u cted , e s p e c ia lly r e g a r d in g th e re s o lu tio n of s e v e r a l m a th e m a tic a l d iffic u ltie s w hen no so lu tio n s s e e m e d to e x is t.T h e N a tio n a l A e ro n a u tic s and Space A d m in is tr a tio n i s th an k ed f o r i t s fin a n c ia l su p p o rt d u rin g the y e a
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 .