The transfer of excitation energy induced in inelastic collisions between excited Hg atoms and ground-state Cd atoms was studied using methods of sensitized fluorescence. Hg atoms in a low-density Hg–Cd vapor mixture were excited with Hg 2537 Å resonance radiation to the 63P1 state and interacted with the Cd atoms which became collisionally excited to the 53P1 state and subsequently decayed emitting sensitized fluorescence. Measurements of relative intensities of Hg 2537 Å resonance fluorescence and Cd 3261 Å sensitized fluorescence yielded the cross section Q(63P1 → 53P1) = 4.6 × 10−2 Å2. The efficiency of the excitation transfer was enhanced by the addition of small quantities of N2 to the Hg–Cd system. The cross section for quenching of the Cd 53P1 state by collisions with N2 was found to be 1.7 Å2.
The transfer of excitation energy induced in inelastic collisions between excited Hg atoms and ground-state Cd atoms was studied using methods of sensitized fluorescence. Hg atoms in a low-density Hg–Cd vapor mixture were excited with Hg 2537 Å resonance radiation to the 63P1 state and interacted with the Cd atoms which became collisionally excited to the 53P1 state and subsequently decayed emitting sensitized fluorescence. Measurements of relative intensities of Hg 2537 Å resonance fluorescence and Cd 3261 Å sensitized fluorescence yielded the cross section Q(63P1 → 53P1) = 4.6 × 10−2 Å2. The efficiency of the excitation transfer was enhanced by the addition of small quantities of N2 to the Hg–Cd system. The cross section for quenching of the Cd 53P1 state by collisions with N2 was found to be 1.7 Å2.
The transfer of excitation energy, induced in inelastic collisions between excited Hg atoms and ground state Zn atoms, was studied using methods of sensitized fluorescence. Hg atoms in a low density Hg–Zn mixture were excited with Hg 2537 Å resonance radiation to the 63P1 state, and interacted with the Zn atoms which became collisionally excited to the 43P1 state and then decayed emitting sensitized fluorescence. Measurements of relative intensities of Hg 2537 Å resonance fluorescence and Zn 3076 Å sensitized fluorescence yielded the cross section of 5.9 × 10−2 Å2 for Hg(63P1) → Zn(43P1) excitation transfer. The addition of small quantities of N2 to the Hg–Zn vapor mixture enhanced the efficiency of the transfer. The cross section for quenching of the Zn 43P1 state by collisions with N2 was found to be 0.19 Å2.
Collisional transfer of excitation energy from cadmium to caesium was investigated using methods of sensitized fluorescence. A mixture of cadmium and caesium vapors at low pressure was irradiated with Cd 3263.0 Å resonance radiation producing a population of Cd (53P1) atoms whose inelastic collisions with ground-state Cs atoms resulted in a transfer of excitation energy to a close-lying S, P, D and F states in caesium. The subsequent decay of these states manifested itself in the emission of sensitized fluorescence spectrum. Intensity measurements on the components of the spectrum by means of energy calibrated detector yielded some 50 cross-section values whose magnitudes range from 0.2 Å2 to 30.0 Å2 and which exhibit a pronounced resonances with ΔE the energy defect between Cd (53P1) and the appropriate level in caesium.
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.
The transfer of excitation from excited mercury atoms to ground-state thallium atoms was investigated using techniques of sensitized fluorescence. A Hg–Tl vapor mixture contained in a quartz cell was irradiated with Hg 2537 Å resonance radiation which caused the mercury atoms to become excited to the 63P1, state. Subsequent collisions between the Hg(63P1) and Tl(62P1/2) atoms resulted in the population of the 82S1/2, 62D, and 72S1/2 thallium states, whose decay gave rise to sensitized fluorescence of wavelengths 3231, 3520, 3776, and 5352 Å. Intensity measurements on the sensitized fluorescence and on the Hg 2537 Å resonance fluorescence, observed at right angles to the direction of excitation, yielded cross sections of 3.0, 0.3, and 0.05 Å2 for collisional excitation transfer from Hg(63P1) to the 82S1/2, 62D, and 72S1/2 states in thallium, respectively. The results are fully consistent with previously determined cross sections for excitation transfer in other binary metallic vapor systems.
Sensitized fluorescence in rubidium vapor, induced by collisions with excited potassium atoms, was investigated to determine the total cross sections for inelastic collisions between excited potassium atoms and rubidium atoms in their ground states. The collision cross sections for the various excitation transfer processes are as follows: Q12′ (K42P1/2 → Rb52P3/2) = 40 Å2, Q22′ (K42P3/2 → Rb52P3/2) = 27 Å2, Q11′ (K42P1/2 → Rb52P1/2) = 2.7 Å2, and Q21′ (K42P3/2 → Rb52P1/2) = 1.9 Å2. The partial pressure of potassium vapor in the K–Rb mixture was kept largely below 10−5 mm Hg to eliminate effects due to the trapping of potassium resonance radiation.
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.