Physical Review

The Effect of Foreign Gases upon the Relative Intensities of the Mercury Triplet 2P0123−2S13 under Conditions of Optical Excitation

R. T. Macdonald, G. K. Rollefson

Published Feb 1, 1933• 2 citations

Abstract

Effect of nitrogen and of mixtures of nitrogen and carbon dioxide upon the fluorescence of mercury vapor. By "stepwise" optical excitation, unexcited mercury atoms are raised to the $2^{3}S_{1}$ state. They may leave this level upon the emission of radiation by four paths---the first to the $2^{1}P_{1}$ state, a transition of relatively low probability, and the other three to the $2^{3}P_{2}$, $2^{3}P_{1}$, and $2^{3}P_{0}$ states with the emission of 5461A, 4358A and 4046A, respectively. Measurements, by totally independent methods, of the mean life of the $2^{3}S_{1}$ state yielded values, when measured by the line 5461A, equal to approximately four times those when measured by either 4358A or 4046A. Upon the addition of foreign gas, then, the intensity ratio of 5461A to either 4358A or 4046A should decrease with increasing pressure while that of 4046A to 4358A should remain constant. However, these ratios were all found to be invariant with pressure, up to 400 mm in the case of nitrogen and up to 100 mm in the case of the nitrogen-carbon dioxide mixtures.

DOI: 10.1103/physrev.43.177

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The Mean Life of the 7S13 State of Mercury from Polarization Measurements on the Visible Triplet

Allan C. G. Mitchell, Edgar J. Murphy

Physical ReviewJul 1, 193412 citations

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

Richard Allen Anderson, Robert H. McFarland

Physical ReviewJul 15, 19609 citations

Transition Probabilities and Quenching in the 3P State of Sodium

N. E. Berry, G. K. Rollefson

Physical ReviewNov 1, 19315 citations

Stepwise Fluorescence in Mercury-Nitrogen Mixtures The 3650 Line

Louis A. Turner

Physical ReviewSep 15, 19372 citations

Hyperfine Structure Absorption in Optically Excited Mercury Vapor

M. L. Pool, S. J. Simmons

Physical ReviewDec 15, 19331 citation

Measurement of the Life of the Metastable Mercury Atom

M. L. Pool

Physical ReviewJan 1, 192914 citations

Physical Review

The Effect of Foreign Gases upon the Relative Intensities of the Mercury Triplet 2P0123−2S13 under Conditions of Optical Excitation

R. T. Macdonald, G. K. Rollefson

Published Feb 1, 1933• 2 citations

Publisher

Abstract

Effect of nitrogen and of mixtures of nitrogen and carbon dioxide upon the fluorescence of mercury vapor. By "stepwise" optical excitation, unexcited mercury atoms are raised to the

2^{3}S_{1}

state. They may leave this level upon the emission of radiation by four paths---the first to the

2^{1}P_{1}

state, a transition of relatively low probability, and the other three to the

2^{3}P_{2}

2^{3}P_{1}

, and

2^{3}P_{0}

states with the emission of 5461A, 4358A and 4046A, respectively. Measurements, by totally independent methods, of the mean life of the

2^{3}S_{1}

state yielded values, when measured by the line 5461A, equal to approximately four times those when measured by either 4358A or 4046A. Upon the addition of foreign gas, then, the intensity ratio of 5461A to either 4358A or 4046A should decrease with increasing pressure while that of 4046A to 4358A should remain constant. However, these ratios were all found to be invariant with pressure, up to 400 mm in the case of nitrogen and up to 100 mm in the case of the nitrogen-carbon dioxide mixtures.

DOI: 10.1103/physrev.43.177

Related papers

The Mean Life of the 7S13 State of Mercury from Polarization Measurements on the Visible Triplet

Allan C. G. Mitchell, Edgar J. Murphy

Fluorescence of the visible triplet lines of mercury (4047, 4358, 5461) was obtained by exciting a mixture of mercury vapor and a small amount of nitrogen by radiation from a quartz mercury arc. The fluorescence was observed at right angles to the exciting light beam and the polarization of each line, isolated by suitable filters, was measured by the method of crossed Wollaston prisms. Measurements in zero magnetic field (polarized excitation) gave 88.2 percent for 4047, -65.5 for 4358, and 14.55 for 5461, compared to theoretical values (broad line excitation) of 84.7, -67.0, and 8.7 percent, respectively. Measurements were then made of the polarization as a function of a magnetic field applied in the observation direction and the mean life of the $7^{3}S_{1}$ state calculated from the data. The mean life of this state as measured by 4047 and 4358 was 0.8\ifmmode\pm\else\textpm\fi{}0.1\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}8}$ sec. at about 3.0 mm nitrogen pressure. The mean life as measured by the line 5461 was about 0.6\ifmmode\pm\else\textpm\fi{}0.1\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}8}$ sec. The collision cross section for the $7^{3}S_{1}$ state against nitrogen was measured by measuring the polarization of 4358 at a field of 3 gauss and varying nitrogen pressures, giving the result ${{\ensuremath{\sigma}}_{q}}^{2}=1.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}$ ${\mathrm{cm}}^{2}$ .Fluorescence of the visible triplet lines of mercury (4047, 4358, 5461) was obtained by exciting a mixture of mercury vapor and a small amount of nitrogen by radiation from a quartz mercury arc. The fluorescence was observed at right angles to the exciting light beam and the polarization of each line, isolated by suitable filters, was measured by the method of crossed Wollaston prisms. Measurements in zero magnetic field (polarized excitation) gave 88.2 percent for 4047, -65.5 for 4358, and 14.55 for 5461, compared to theoretical values (broad line excitation) of 84.7, -67.0, and 8.7 percent, respectively. Measurements were then made of the polarization as a function of a magnetic field applied in the observation direction and the mean life of the $7^{3}S_{1}$ state calculated from the data. The mean life of this state as measured by 4047 and 4358 was 0.8\ifmmode\pm\else\textpm\fi{}0.1\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}8}$ sec. at about 3.0 mm nitrogen pressure. The mean life as measured by the line 5461 was about 0.6\ifmmode\pm\else\textpm\fi{}0.1\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}8}$ sec. The collision cross section for the $7^{3}S_{1}$ state against nitrogen was measured by measuring the polarization of 4358 at a field of 3 gauss and varying nitrogen pressures, giving the result ${{\ensuremath{\sigma}}_{q}}^{2}=1.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}$ ${\mathrm{cm}}^{2}$.

Physical ReviewJul 1, 193412 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.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 ReviewJul 15, 19609 citations

Transition Probabilities and Quenching in the 3P State of Sodium

N. E. Berry, G. K. Rollefson

The effect of foreign gases upon the fluorescence of sodium vapor excited by the second line of the principal series has been investigated. The gases used were helium, nitrogen, and hydrogen and the intensities of both the 3303A line and the $D$ light were observed. From the variation in intensity of the 3303A line as gas is added it is concluded that the presence of an inert gas has no appreciable effect upon the relative transition probabilities in the ${3}^{2}P$ state of sodium. With nitrogen or hydrogen as the added gas the $D$ light intensity variation followed that of the 3303A line very closely but with helium a marked increase in intensity was produced by the first gas added with a decrease at higher pressures. This increase was explained as due to a transfer of sodium atoms from the ${3}^{2}P$ to the ${3}^{2}D$ state by collisions, thus increasing the number of atoms which radiate the $D$ light. In addition to this increase in number the collisional transfers produced an increased "Doppler width" in the $D$ light which persisted up to pressures well over 100 mm of helium and caused a decreased absorption of the fluorescence light. The bearing of this work on the difference in the intensity ratio of the ${2}^{2}S\ensuremath{-}{3}^{2}P$ and ${1}^{2}S\ensuremath{-}{3}^{2}P$ transitions as reported by Weiss for an arc and by Christensen and Rollefson in fluorescence is discussed. It is concluded on the basis of experimental evidence that any explanation of the difference which depends upon multiplicity of the ${3}^{2}P$ state is incorrect. An explanation of this difference based upon the assumption that the life period of an excited atom varies inversely as the transition probability of the radiation emitted is presented. It is shown that recent work on the life periods of atoms in the ${2}^{3}{S}_{1}$ state of mercury at least partially supports this assumption. A new type of sodium arc with increased intensity and stability of operation is described.The effect of foreign gases upon the fluorescence of sodium vapor excited by the second line of the principal series has been investigated. The gases used were helium, nitrogen, and hydrogen and the intensities of both the 3303A line and the $D$ light were observed. From the variation in intensity of the 3303A line as gas is added it is concluded that the presence of an inert gas has no appreciable effect upon the relative transition probabilities in the ${3}^{2}P$ state of sodium. With nitrogen or hydrogen as the added gas the $D$ light intensity variation followed that of the 3303A line very closely but with helium a marked increase in intensity was produced by the first gas added with a decrease at higher pressures. This increase was explained as due to a transfer of sodium atoms from the ${3}^{2}P$ to the ${3}^{2}D$ state by collisions, thus increasing the number of atoms which radiate the $D$ light. In addition to this increase in number the collisional transfers produced an increased "Doppler width" in the $D$ light which persisted up to pressures well over 100 mm of helium and caused a decreased absorption of the fluorescence light. The bearing of this work on the difference in the intensity ratio of the ${2}^{2}S\ensuremath{-}{3}^{2}P$ and ${1}^{2}S\ensuremath{-}{3}^{2}P$ transitions as reported by Weiss for an arc and by Christensen and Rollefson in fluorescence is discussed. It is concluded on the basis of experimental evidence that any explanation of the difference which depends upon multiplicity of the ${3}^{2}P$ state is incorrect. An explanation of this difference based upon the assumption that the life period of an excited atom varies inversely as the transition probability of the radiation emitted is presented. It is shown that recent work on the life periods of atoms in the ${2}^{3}{S}_{1}$ state of mercury at least partially supports this assumption. A new type of sodium arc with increased intensity and stability of operation is described.

Physical ReviewNov 1, 19315 citations

Stepwise Fluorescence in Mercury-Nitrogen Mixtures The 3650 Line

Louis A. Turner

The experiments of Wood and of Gaviola show that when mercury vapor is illuminated by light from a mercury arc, and nitrogen is added in increasing amounts, the concentration of atoms in the $^{3}P_{2}$ state passes through a minimum. No simple theory accounts for this result. An explanation involving excitation of atoms in the $^{3}P_{1}$ state by vibrating nitrogen molecules is discussed. The results obtained when a filter of bromine vapor is used indicate a transfer of excited mercury atoms from one to another $^{3}D$ state upon collision with nitrogen.The experiments of Wood and of Gaviola show that when mercury vapor is illuminated by light from a mercury arc, and nitrogen is added in increasing amounts, the concentration of atoms in the $^{3}P_{2}$ state passes through a minimum. No simple theory accounts for this result. An explanation involving excitation of atoms in the $^{3}P_{1}$ state by vibrating nitrogen molecules is discussed. The results obtained when a filter of bromine vapor is used indicate a transfer of excited mercury atoms from one to another $^{3}D$ state upon collision with nitrogen.

Physical ReviewSep 15, 19372 citations

Hyperfine Structure Absorption in Optically Excited Mercury Vapor

M. L. Pool, S. J. Simmons

The radiation 4047, 2967 and 2752, all terminating on the $2^{3}P_{0}$ state of mercury, was passed through optically excited mercury vapor and the absorption of each wavelength for various lengths of excited vapor and for various pressures of admixed nitrogen was measured photometrically. With low dispersion the intensity of 2752 decreased nearly exponentially with increase in length of excited vapor giving a constant linear absorption coefficient. But the lines 4047 and 2967 were found not to obey the exponential law, the fractional decrease in intensity per unit length of path decreased rapidly as the total length of the absorbing vapor increased. With high dispersion the absorption of the five components of 4047 was strong and increased with increase of admixed nitrogen. The strongest component showed the strongest absorption and the amount of absorption decreased with decrease in intensity of components. The intensity of each component decreased nearly exponentially with increase in length of excited mercury vapor. Both components of 2967 showed strong absorption. None of the components of 4358 or 5461 showed measurable absorption.The radiation 4047, 2967 and 2752, all terminating on the $2^{3}P_{0}$ state of mercury, was passed through optically excited mercury vapor and the absorption of each wavelength for various lengths of excited vapor and for various pressures of admixed nitrogen was measured photometrically. With low dispersion the intensity of 2752 decreased nearly exponentially with increase in length of excited vapor giving a constant linear absorption coefficient. But the lines 4047 and 2967 were found not to obey the exponential law, the fractional decrease in intensity per unit length of path decreased rapidly as the total length of the absorbing vapor increased. With high dispersion the absorption of the five components of 4047 was strong and increased with increase of admixed nitrogen. The strongest component showed the strongest absorption and the amount of absorption decreased with decrease in intensity of components. The intensity of each component decreased nearly exponentially with increase in length of excited mercury vapor. Both components of 2967 showed strong absorption. None of the components of 4358 or 5461 showed measurable absorption.

Physical ReviewDec 15, 19331 citation

Measurement of the Life of the Metastable Mercury Atom

M. L. Pool

Half value time for the ${2}^{3}$ ${\mathrm{P}}_{0}$ state of Hg for various pressures of admixed ${\mathrm{N}}_{2}$ --- A high speed rotating disk has been used to interrupt the total radiation from a water-cooled and magnetically controlled quartz mercury arc before optically exciting mercury vapor in a quartz resonance tube at room temperature. In the neighborhood of ${10}^{\ensuremath{-}4}$ sec. after the optical excitation a flash of visible radiation from another water-cooled and magnetically controlled mercury arc was passed through the resonance tube and the absorption spectrum photographed. The line 4047 ($2^{3}P_{0}\ensuremath{-}2^{3}S_{1}$) showed strong absorption when a few millimeters of nitrogen were introduced into the resonance tube. The lines 4077, 4358, 5461, 5770 and 5790 showed no measurable absorption under similar conditions. The rate of decay of the amount of 4047 absorbed with respect to the time-wait after excitation of the mercury vapor was taken as the rate of decay of the metastable $2^{3}P_{0}$ state. The life or half-value time of the state was found to vary markedly with the pressure of admixed nitrogen. The maximum life 4.2\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}4}$ sec. occurred for 6.8 mm of nitrogen. No absorption of 4047 was observed upon the introduction of hydrogen, argon, neon, or helium into the resonance tube.Half value time for the ${2}^{3}$${\mathrm{P}}_{0}$ state of Hg for various pressures of admixed ${\mathrm{N}}_{2}$--- A high speed rotating disk has been used to interrupt the total radiation from a water-cooled and magnetically controlled quartz mercury arc before optically exciting mercury vapor in a quartz resonance tube at room temperature. In the neighborhood of ${10}^{\ensuremath{-}4}$ sec. after the optical excitation a flash of visible radiation from another water-cooled and magnetically controlled mercury arc was passed through the resonance tube and the absorption spectrum photographed. The line 4047 ($2^{3}P_{0}\ensuremath{-}2^{3}S_{1}$) showed strong absorption when a few millimeters of nitrogen were introduced into the resonance tube. The lines 4077, 4358, 5461, 5770 and 5790 showed no measurable absorption under similar conditions. The rate of decay of the amount of 4047 absorbed with respect to the time-wait after excitation of the mercury vapor was taken as the rate of decay of the metastable $2^{3}P_{0}$ state. The life or half-value time of the state was found to vary markedly with the pressure of admixed nitrogen. The maximum life 4.2\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}4}$ sec. occurred for 6.8 mm of nitrogen. No absorption of 4047 was observed upon the introduction of hydrogen, argon, neon, or helium into the resonance tube.

Physical ReviewJan 1, 192914 citations

Effect of nitrogen and of mixtures of nitrogen and carbon dioxide upon the fluorescence of mercury vapor. By "stepwise" optical excitation, unexcited mercury atoms are raised to the

2^{3}S_{1}

state. They may leave this level upon the emission of radiation by four paths---the first to the

2^{1}P_{1}

state, a transition of relatively low probability, and the other three to the

2^{3}P_{2}

2^{3}P_{1}

, and

2^{3}P_{0}

states with the emission of 5461A, 4358A and 4046A, respectively. Measurements, by totally independent methods, of the mean life of the

2^{3}S_{1}

7^{3}S_{1}

state calculated from the data. The mean life of this state as measured by 4047 and 4358 was 0.8\ifmmode\pm\else\textpm\fi{}0.1\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}8}$ sec. at about 3.0 mm nitrogen pressure. The mean life as measured by the line 5461 was about 0.6\ifmmode\pm\else\textpm\fi{}0.1\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}8}$ sec. The collision cross section for the

7^{3}S_{1}

state against nitrogen was measured by measuring the polarization of 4358 at a field of 3 gauss and varying nitrogen pressures, giving the result ${{\ensuremath{\sigma}}_{q}}^{2}=1.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}$

{\mathrm{cm}}^{2}

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.

D

light were observed. From the variation in intensity of the 3303A line as gas is added it is concluded that the presence of an inert gas has no appreciable effect upon the relative transition probabilities in the

{3}^{2}P

state of sodium. With nitrogen or hydrogen as the added gas the

D

light intensity variation followed that of the 3303A line very closely but with helium a marked increase in intensity was produced by the first gas added with a decrease at higher pressures. This increase was explained as due to a transfer of sodium atoms from the

{3}^{2}P

to the

{3}^{2}D

state by collisions, thus increasing the number of atoms which radiate the

D

light. In addition to this increase in number the collisional transfers produced an increased "Doppler width" in the

D

light which persisted up to pressures well over 100 mm of helium and caused a decreased absorption of the fluorescence light. The bearing of this work on the difference in the intensity ratio of the ${2}^{2}S\ensuremath{-}{3}^{2}P$ and ${1}^{2}S\ensuremath{-}{3}^{2}P$ transitions as reported by Weiss for an arc and by Christensen and Rollefson in fluorescence is discussed. It is concluded on the basis of experimental evidence that any explanation of the difference which depends upon multiplicity of the

{3}^{2}P

state is incorrect. An explanation of this difference based upon the assumption that the life period of an excited atom varies inversely as the transition probability of the radiation emitted is presented. It is shown that recent work on the life periods of atoms in the

{2}^{3}{S}_{1}

state of mercury at least partially supports this assumption. A new type of sodium arc with increased intensity and stability of operation is described.

The experiments of Wood and of Gaviola show that when mercury vapor is illuminated by light from a mercury arc, and nitrogen is added in increasing amounts, the concentration of atoms in the

^{3}P_{2}

state passes through a minimum. No simple theory accounts for this result. An explanation involving excitation of atoms in the

^{3}P_{1}

state by vibrating nitrogen molecules is discussed. The results obtained when a filter of bromine vapor is used indicate a transfer of excited mercury atoms from one to another

^{3}D

state upon collision with nitrogen.

The radiation 4047, 2967 and 2752, all terminating on the

2^{3}P_{0}

state of mercury, was passed through optically excited mercury vapor and the absorption of each wavelength for various lengths of excited vapor and for various pressures of admixed nitrogen was measured photometrically. With low dispersion the intensity of 2752 decreased nearly exponentially with increase in length of excited vapor giving a constant linear absorption coefficient. But the lines 4047 and 2967 were found not to obey the exponential law, the fractional decrease in intensity per unit length of path decreased rapidly as the total length of the absorbing vapor increased. With high dispersion the absorption of the five components of 4047 was strong and increased with increase of admixed nitrogen. The strongest component showed the strongest absorption and the amount of absorption decreased with decrease in intensity of components. The intensity of each component decreased nearly exponentially with increase in length of excited mercury vapor. Both components of 2967 showed strong absorption. None of the components of 4358 or 5461 showed measurable absorption.

Half value time for the

{2}^{3}

{\mathrm{P}}_{0}

state of Hg for various pressures of admixed

{\mathrm{N}}_{2}

--- A high speed rotating disk has been used to interrupt the total radiation from a water-cooled and magnetically controlled quartz mercury arc before optically exciting mercury vapor in a quartz resonance tube at room temperature. In the neighborhood of ${10}^{\ensuremath{-}4}$ sec. after the optical excitation a flash of visible radiation from another water-cooled and magnetically controlled mercury arc was passed through the resonance tube and the absorption spectrum photographed. The line 4047 ($2^{3}P_{0}\ensuremath{-}2^{3}S_{1}$) showed strong absorption when a few millimeters of nitrogen were introduced into the resonance tube. The lines 4077, 4358, 5461, 5770 and 5790 showed no measurable absorption under similar conditions. The rate of decay of the amount of 4047 absorbed with respect to the time-wait after excitation of the mercury vapor was taken as the rate of decay of the metastable

2^{3}P_{0}

state. The life or half-value time of the state was found to vary markedly with the pressure of admixed nitrogen. The maximum life 4.2\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}4}$ sec. occurred for 6.8 mm of nitrogen. No absorption of 4047 was observed upon the introduction of hydrogen, argon, neon, or helium into the resonance tube.