The cross sections for 72P1/2–72P3/2 excitation transfer in cesium, induced in collisions with noble gas atoms, have been determined in a series of sensitized fluorescence experiments at temperatures ranging from 405 to 630 K. The cross sections which lie in the range 0.06–20 Å2, exhibit a temperature dependence which, however, is less pronounced than in the more adiabatic case of the cesium resonance doublet.

Excitation transfer between the 62P fine-structure substates in rubidium, induced in inelastic collisions with ground-state molecules, has been studied using techniques of sensitized fluorescence. Rubidium vapor in mixtures with various molecular gases was irradiated with each component of the 2P rubidium doublet in turn, and measurements of sensitized-to-resonance fluorescent intensity ratios yielded the following mixing cross sections Q12(2P1/2 → 2P3/2) and Q21(2P1/2 ← 2P3/2), as well as effective quenching cross sections Q1X(2P1/2 → 2XJ″) and Q2X(2P3/2 → 2XJ″). For collisions with H2: Q12(2P1/2 → 2P3/2) = (41 ± 5) Å2; Q21(2P1/2 ← 2P3/2) = (26 ± 3) Å2; Q1X(2P1/2 → 2XJ″) = (36 ± 9) Å2; Q2X(2P3/2 → 2XJ″) = (31 ± 8) Å2. For HD: Q12 = (42 ± 5) Å2; Q21 = (27 ± 4) Å2; Q1X = (47 ± 13) Å2; Q2X = (38 ± 10) Å2. For D2: Q12 = (42 ± 5) Å2; Q21 = (27 ± 4) Å2; Q1X = (28 ± 8) Å2; Q2X = (21 ± 7) Å2. For N2: Q12 = (107 ± 15) Å2; Q21 = (70 ± 10) Å2; Q1X = (128 ± 44) Å2; Q2X = (126 ± 33) Å2. For CH4: Q12 = (38 ± 6) Å2; Q21 = (24 ± 3) Å2; Q1X = (129 ± 41) Å2; Q2X = (114 ± 37) Å2. For CD4: Q12 = (52 ± 7) Å2; Q21 = (34 ± 5) Å2; Q1X = (82 ± 30) Å2; Q2X = (76 ± 22) Å2. An analysis of these results suggests the possibility of resonances with various molecular rotational and vibrational transitions.

The temperature dependence of cross sections for PI,? CJ 7'P3,? excitation transfer in ccsium. as well as the effective quenching of these states, induced in collisions with Hz, N' . CH,. and CD, molecules have bccn invcstigatcd in a scrics of sensitized fluorescence cxperiments over a temperature range 390-640 K. Thc 7 '~ mixing cross scctions are of the order of 10-l5 cm' and exceed by at least one order of magnitude similar cross sections for mixing by collisions with Ne, Ar, Kr, and Xe. The large sizes of the mixing cross sections and their variation with temperature are ascribcd to a phenomenon of electronic-to-rotational energy transfer.On a etudiC la variation en fonction dc la temperature des sections efficaces pour Ic transfert d'cxcitation 7'P1,, t , 7 '~> ,~ dans le cesium de mCme que I'extinction effective de ccs Ctats. sous I'effet de collisions avec des molCculcs H', N'. CH, ct CD,, dans une sCrie d'expkriences de fluorescence sensibilisee, sur un intervalle de te~nperaturc allant dc 390 h 640 K. Les sections efficaces de melange 7 '~ sont de I'ordrc de cm' ct dipassent par au moins un ordre dc grandcur Ics sections efficaces semblables dc melange par collisions avcc Ne, Ar, Kr ct Xe. Les valeurs considerables de ccs sections efficaces et leur variation en fonction de la temperature sont attribuees h un phinomene dc transfert d'Cncrgic electronique i Cncrgic rotationnelle.[Traduit par le journal]Can.

The cross sections for excitation transfer between the 62P fine-structure substates in rubidium, induced in collisions with noble gas atoms, have been determined in a series of sensitized fluorescence experiments. Mixtures of rubidium vapor and noble gases at pressures varying in the range 0–5 Torr were irradiated with each component of the second 2P rubidium doublet in turn and the following cross sections for 2P mixing were obtained from measurements of sensitised-to-resonance fluorescent intensity ratios. Rb–He: Q12(2P1/2 → 2P3/2) = 29.3 Å2; Q21(2P1/2 ← 2P3/2) = 19.0 Å2. Rb–Ne: Q12 = 10.3 Å2; Q21 = 6.4 Å2. Rb–Ar: Q12 = 24.0 Å2; Q21 = 14.9 Å2. Rb–Kr: Q12 = 23.2 Å2; Q21 = 14.6 Å2. Rb–Xe: Q12 = 43.9 Å2; Q21 = 27.7 Å2 In their dependence on the magnitude of the fine-structure splitting, the values are consistent with previously determined cross sections for mixing in the first and third 2P doublets of alkali atoms.

The formation and decay of Hg2 molecules in their 'l"and 'O"states, produced in Hg-Ar mixtures irradiated with 2537-A Hg resonance radiation, has been investigated by the method of delayed coincidences. The mixtures which consisted of Hg vapor at a pressure of about 1 Torr and Ar at pressures of 45-720 Torr and which were contained in a quartz fluorescence cell, were excited with 0 pulses of light, and the decay spectra of the 3350and 4850-A molecular fluorescent bands were studied in relation to Ar pressure. Analysis of the decays indicates that the effective cross sections for '1"-'O"mixing, induced in Hg, -Ar collisions are of the same order as the Hg2-N, mixing cross sections, leading to the conclusion that the 4850-A band is emitted mainly by O"molecules in high vibrational states.