Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review

Experimental Determination of the De-excitation Cross Section for the 6P13 State of Mercury by Thallium

B. C. Hudson, B. Curnutte

Published Aug 5, 1966• 6 citations
Publisher

Abstract

The de-excitation or quenching cross section of thallium for the $6^{3}P_{1}$ state of mercury has been obtained over a range of temperatures of 800 to 900\ifmmode^\circ\else\textdegree\fi{}C. Comparison of the resonance fluorescence from a mercury-thallium vapor mixture with the resonance fluorescence from a pure mercury vapor at the same number density, as determined by line absorption, allows the calculation of the de-excitation cross section. The present data together with Garrett's value of the lifetime of the $6^{3}P_{1}$ state of mercury and existing data on the vapor pressures of mercury and thallium were used to obtain values of the de-excitation cross section. Values of the cross section range from 108\ifmmode\pm\else\textpm\fi{}41 ${\mathrm{\AA{}}}^{2}$ at 800\ifmmode^\circ\else\textdegree\fi{}C to 80\ifmmode\pm\else\textpm\fi{}19 ${\mathrm{\AA{}}}^{2}$ at 900\ifmmode^\circ\else\textdegree\fi{}C. The corresponding quenching-rate coefficients varied from (5.1\ifmmode\pm\else\textpm\fi{}1.9)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}7}$ ${\mathrm{cm}}^{3}$/sec at 800\ifmmode^\circ\else\textdegree\fi{}C to (4.0\ifmmode\pm\else\textpm\fi{}0.9)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}7}$ ${\mathrm{cm}}^{3}$/sec at 900\ifmmode^\circ\else\textdegree\fi{}C.

DOI
10.1103/physrev.148.60

Related papers

Experimental Determination of the Excitation Transfer Cross Section from the 6P13 and 6P03 States of Mercury to Thallium

B. C. Hudson, B. Curnutte

The excitation transfer cross sections to several of the excited states of thallium from the $6^{3}P_{1}$ and $6^{3}P_{0}$ states of mercury have been obtained at various temperatures in the range 800\ifmmode^\circ\else\textdegree\fi{}C to 900\ifmmode^\circ\else\textdegree\fi{}C. Analysis of the equilibrium rates of absorption, emission, and collision processes allows the calculation of excitation transfer cross sections from experimentally determined ratios of intensities of thallium-sensitized fluorescence lines to the intensity of mercury resonance fluorescence, using calculated values of the thallium transition probabilities. The values obtained for the excitation transfer cross sections are comparable in magnitude with collision cross sections based on considerations of gas kinetics.

Physical Review•Dec 2, 1966•4 citations

The Quenching of Mercury Resonance Radiation (2537A) by Nitrogen

C. G. Matland

When a mercury atom in the resonance $6^{3}P_{1}$ state collides with a nitrogen molecule, it may be transferred to the metastable $6^{3}P_{0}$ state. The cross section for this reaction has been measured by a new method. Mercury vapor, in the presence of a known pressure of nitrogen gas, is excited by 2537A radiation. After the source of the excitation is cut off, the decay time of the imprisoned radiation is observed. The quenching collision cross section ${\ensuremath{\sigma}}_{Q}$ is calculated from the measured decay time and the known value of the imprisonment time in the absence of the quenching gas. Measurements have been taken over the temperature range 325-525\ifmmode^\circ\else\textdegree\fi{}K; ${\ensuremath{\sigma}}_{Q}$ is found to increase from 5.0\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}17}$ ${\mathrm{cm}}^{2}$ at the lower temperature to 1.0\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}16}$ ${\mathrm{cm}}^{2}$ at the upper temperature.

Physical Review•Nov 1, 1953•32 citations

6P13−6P03 Excitation Transfer in Mercury, Induced in Collisions with N2 Molecules

John M. Pitre, K. Hammond, L. Krause

The cross section for the transition $6^{3}P_{0}\ensuremath{\rightarrow}6^{3}P_{1}$ in mercury, induced in collisions with ${\mathrm{N}}_{2}$ molecules, has been determined by the method of delayed coincidences. The Hg $^{3}P_{1}$ state was excited by pulses of 2537-\AA{} Hg resonance radiation and the decay of the long-lived 2537-\AA{} afterglow was studied in relation to ${\mathrm{N}}_{2}$ pressure. The resulting cross section ${Q}_{12}(^{3}P_{0}\ensuremath{\rightarrow}^{3}P_{1})=4.18\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ ${\mathrm{\AA{}}}^{2}$ was found to be good agreement with the prediction of the principle of detailed balancing when compared with the cross section ${Q}_{21}(^{3}P_{1}\ensuremath{\rightarrow}^{3}P_{0})$. It was also found that, within the sensitivity of the method, collisions with ${\mathrm{N}}_{2}$ molecules do not quench $^{3}P_{1}$ or $^{3}P_{0}$ Hg atoms to the ground state.

Physical Review A•Dec 1, 1972•39 citations

Sensitized fluorescence in thallium induced in collisions with Hg(63P1) atoms

Murray K Wade, M. Czajkowski, L. Krause

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.

Canadian Journal of Physics•Jul 1, 1978•10 citations

The Metastable 2 p 3 -State of Mercury Atoms

S. Loria

Let us consider a mixture of mercury vapor, thallium vapor and nitrogen in a closed quartz tube under well defined conditions of pressure and temperature, illuminated by λ 2537A of constant intensity. \n \nDue to the absorption of the illuminating radiation a constant number N of mercury atoms will be activated in unit time. Those activated atoms persist in the 2p2-state for a finite time t which is known to be of the order of magnitude of 10^-7 sec [1]. If they escape collision during this period they return to their normal state in the ordinary wave-emitting radiation (resonance). They may, however, while activated, collide with nitrogen molecules, normal mercury atoms or normal thallium atoms. We shall assume, for the present, that the amount of nitrogen and thallium sufficiently exceeds the amount of mercury, so that we may disregard totally the collisions between activated and normal mercury atoms. \n \nWe assume furthermore that all collisions between activated mercury atoms and thallium atoms result in the activation of the latter, producing the fluorescence radiation of thallium with a constant energy distribution between its different lines.

Proceedings of the National Academy of Sciences•Nov 1, 1925•3 citations

Effects of Added Gases on the Sensitized Fluorescence Spectrum of a Hg-Tl Mixture

Richard Allen Anderson, Robert H. McFarland

An investigation of the sensitized fluorescence of a mercury thallium mixture without and with the addition of argon and helium gases is discussed. Data taken without the addition of foreign gases are used to extend the theory of Frish and Karaulinya to a mercury thallium mixture. Relative collision cross sections for the excitation of the thallium energy states, $9^{2}S_{\frac{1}{2}}$, $7^{2}D_{\frac{5}{2},\frac{3}{2}}$, $8^{2}S_{\frac{1}{2}}$, $6^{2}D_{\frac{5}{2}}$, and $6^{2}D_{\frac{3}{2}}$ were calculated for mercury thallium collisions. Data taken with the addition of argon and helium gases are given to indicate the variation of the intensity of the thallium lines as a function of argon and helium gas pressures at one constant thallium and three mercury temperatures. The explanation of the results depends on the role of mercury $6^{3}P_{1}$ excited atoms, metastable atoms, and mercury molecules in collision with thallium atoms for energy exchange, and also requires the use of Winans' partial selection rule and other generally accepted ideas concerning energy transfer, emission, and absorption.

Physical Review•Jul 15, 1960•9 citations
The de-excitation or quenching cross section of thallium for the 63P16^{3}P_{1}63P1​ state of mercury has been obtained over a range of temperatures of 800 to 900\ifmmode^\circ\else\textdegree\fi{}C. Comparison of the resonance fluorescence from a mercury-thallium vapor mixture with the resonance fluorescence from a pure mercury vapor at the same number density, as determined by line absorption, allows the calculation of the de-excitation cross section. The present data together with Garrett's value of the lifetime of the 63P16^{3}P_{1}63P1​ state of mercury and existing data on the vapor pressures of mercury and thallium were used to obtain values of the de-excitation cross section. Values of the cross section range from 108\ifmmode\pm\else\textpm\fi{}41 A˚2{\mathrm{\AA{}}}^{2}A˚2 at 800\ifmmode^\circ\else\textdegree\fi{}C to 80\ifmmode\pm\else\textpm\fi{}19 A˚2{\mathrm{\AA{}}}^{2}A˚2 at 900\ifmmode^\circ\else\textdegree\fi{}C. The corresponding quenching-rate coefficients varied from (5.1\ifmmode\pm\else\textpm\fi{}1.9)\ifmmode\times\else\texttimes\fi{}10\ensuremath−7{10}^{\ensuremath{-}7}10\ensuremath−7 cm3{\mathrm{cm}}^{3}cm3/sec at 800\ifmmode^\circ\else\textdegree\fi{}C to (4.0\ifmmode\pm\else\textpm\fi{}0.9)\ifmmode\times\else\texttimes\fi{}10\ensuremath−7{10}^{\ensuremath{-}7}10\ensuremath−7 cm3{\mathrm{cm}}^{3}cm3/sec at 900\ifmmode^\circ\else\textdegree\fi{}C.
The excitation transfer cross sections to several of the excited states of thallium from the 63P16^{3}P_{1}63P1​ and 63P06^{3}P_{0}63P0​ states of mercury have been obtained at various temperatures in the range 800\ifmmode^\circ\else\textdegree\fi{}C to 900\ifmmode^\circ\else\textdegree\fi{}C. Analysis of the equilibrium rates of absorption, emission, and collision processes allows the calculation of excitation transfer cross sections from experimentally determined ratios of intensities of thallium-sensitized fluorescence lines to the intensity of mercury resonance fluorescence, using calculated values of the thallium transition probabilities. The values obtained for the excitation transfer cross sections are comparable in magnitude with collision cross sections based on considerations of gas kinetics.
When a mercury atom in the resonance 63P16^{3}P_{1}63P1​ state collides with a nitrogen molecule, it may be transferred to the metastable 63P06^{3}P_{0}63P0​ state. The cross section for this reaction has been measured by a new method. Mercury vapor, in the presence of a known pressure of nitrogen gas, is excited by 2537A radiation. After the source of the excitation is cut off, the decay time of the imprisoned radiation is observed. The quenching collision cross section ${\ensuremath{\sigma}}_{Q}$ is calculated from the measured decay time and the known value of the imprisonment time in the absence of the quenching gas. Measurements have been taken over the temperature range 325-525\ifmmode^\circ\else\textdegree\fi{}K; ${\ensuremath{\sigma}}_{Q}$ is found to increase from 5.0\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}17}$ cm2{\mathrm{cm}}^{2}cm2 at the lower temperature to 1.0\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}16}$ cm2{\mathrm{cm}}^{2}cm2 at the upper temperature.
The cross section for the transition $6^{3}P_{0}\ensuremath{\rightarrow}6^{3}P_{1}$ in mercury, induced in collisions with N2{\mathrm{N}}_{2}N2​ molecules, has been determined by the method of delayed coincidences. The Hg 3P1^{3}P_{1}3P1​ state was excited by pulses of 2537-\AA{} Hg resonance radiation and the decay of the long-lived 2537-\AA{} afterglow was studied in relation to N2{\mathrm{N}}_{2}N2​ pressure. The resulting cross section ${Q}_{12}(^{3}P_{0}\ensuremath{\rightarrow}^{3}P_{1})=4.18\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ A˚2{\mathrm{\AA{}}}^{2}A˚2 was found to be good agreement with the prediction of the principle of detailed balancing when compared with the cross section ${Q}_{21}(^{3}P_{1}\ensuremath{\rightarrow}^{3}P_{0})$. It was also found that, within the sensitivity of the method, collisions with N2{\mathrm{N}}_{2}N2​ molecules do not quench 3P1^{3}P_{1}3P1​ or 3P0^{3}P_{0}3P0​ Hg atoms to the ground state.
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.
Let us consider a mixture of mercury vapor, thallium vapor and nitrogen in a closed quartz tube under well defined conditions of pressure and temperature, illuminated by λ 2537A of constant intensity. \n \nDue to the absorption of the illuminating radiation a constant number N of mercury atoms will be activated in unit time. Those activated atoms persist in the 2p2-state for a finite time t which is known to be of the order of magnitude of 10^-7 sec [1]. If they escape collision during this period they return to their normal state in the ordinary wave-emitting radiation (resonance). They may, however, while activated, collide with nitrogen molecules, normal mercury atoms or normal thallium atoms. We shall assume, for the present, that the amount of nitrogen and thallium sufficiently exceeds the amount of mercury, so that we may disregard totally the collisions between activated and normal mercury atoms. \n \nWe assume furthermore that all collisions between activated mercury atoms and thallium atoms result in the activation of the latter, producing the fluorescence radiation of thallium with a constant energy distribution between its different lines.
An investigation of the sensitized fluorescence of a mercury thallium mixture without and with the addition of argon and helium gases is discussed. Data taken without the addition of foreign gases are used to extend the theory of Frish and Karaulinya to a mercury thallium mixture. Relative collision cross sections for the excitation of the thallium energy states, 92S129^{2}S_{\frac{1}{2}}92S21​​, 72D52,327^{2}D_{\frac{5}{2},\frac{3}{2}}72D25​,23​​, 82S128^{2}S_{\frac{1}{2}}82S21​​, 62D526^{2}D_{\frac{5}{2}}62D25​​, and 62D326^{2}D_{\frac{3}{2}}62D23​​ were calculated for mercury thallium collisions. Data taken with the addition of argon and helium gases are given to indicate the variation of the intensity of the thallium lines as a function of argon and helium gas pressures at one constant thallium and three mercury temperatures. The explanation of the results depends on the role of mercury 63P16^{3}P_{1}63P1​ excited atoms, metastable atoms, and mercury molecules in collision with thallium atoms for energy exchange, and also requires the use of Winans' partial selection rule and other generally accepted ideas concerning energy transfer, emission, and absorption.