Collisional transfer of excitation from mercury to sodium was investigated using methods of sensitized fluorescence. A mixture of mercury and sodium vapors at low pressure was irradiated with Hg 2537 Å resonance radiation, producing a population of Hg(63P1) atoms whose inelastic collisions with ground-state sodium atoms resulted in a transfer of excitation energy to close-lying S, P, and D states in sodium. The subsequent decay of these states manifested itself in the emission of a sensitized fluorescent spectrum. Absolute intensity measurements on the components of the spectrum yielded 21 cross sections whose magnitudes range from 0.02 to 38.5 Å2 and which exhibit a pronounced resonance with ΔE, the energy defect between Hg (63P1) and the appropriate level in sodium.
P^2P3/2 m ^-x^n8 *n sodium vapour, induced by inelastic collisions with the diatomic molecules HD, and N^, was studied using techniques of sensitized fluorescence.The mixtures of sodium vapour with the various molecular gases were irradiated with one component of the appropriate resonance doublet.The fluorescence which contained both components of the doublet, was monitored at right angles to the direction of excitation.The measurement of the relative intensities of the fluorescent components 2 yielded the total inelastic cross sections for P mixing, Ql2(2Pi/2---> 2p3/2^ and ^21^2pi/2^---' 2p3/2^* The sodium vaPour *n 5. Cross Sections for 3 P. ---3 P. Mixing Induced by Sodium Molecule Collisions.38 6. Cross Sections for Excitation Transfer in Na-Molecule Collisions, together with the Corresponding Relative Velocity of the Colliding Partners 42 2 2 7. Comparison of the Cross Sections for P. ---^-s/o Mixing Induced by Alkali Atom-Molecule Collisions 43 vi
3 2P1/2 ↔ 3 2P3/2 excitation transfer in sodium, induced in inelastic collisions with ground-state N2, H2, HD, and D2 molecules, has been investigated in a series of sensitized fluorescence experiments. Mixtures of sodium vapor at a pressure of 5 × 10−7 Torr, and the gases, were irradiated with each NaD component in turn, and the fluorescence which contained both D components was monitored at right angles to the direction of the exciting beam. Measurements of the relative intensities of the NaD fluorescent components yielded the following collision cross sections for excitation transfer. For Na–N2 collisions: Q12(2P1/2 → P3/2) = 144 Å2, Q21(2P1,2 ← 2P3/2) = 76 Å2 for Na–H2 collisions: Q12 = 80 Å2, Q21 = 42 Å2. For Na–HD collisions: Q12 = 84 Å2, Q21 = 44 Å2. For Na–D2 collisions: Q12 = 98 Å2, Q21 = 52 Å2. The cross sections Q21 exhibit a slight resonance effect between the atomic and molecular rotational transitions.