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Physical Review A

Excitation transfer in barium by collisions with noble gases

J. Brust, Alan C. Gallagher

Published Sep 1, 1995• 34 citations
Publisher

Abstract

We present a time resolved study of excitation transfer processes between the low lying excited states of barium (6s6p $^{3}$${\mathit{P}}_{\mathit{J}}$, 6s5d $^{1}$${\mathit{D}}_{2}$, 6s5d $^{3}$${\mathit{D}}_{\mathit{J}}$) induced by collisions with noble gases. The transient excited state populations have been measured by means of fluorescence and absorption spectroscopy. Cross sections for spin-changing collisions from $^{3}$${\mathit{P}}_{1}$ to $^{1}$${\mathit{D}}_{2}$ and from $^{1}$${\mathit{D}}_{2}$ to $^{3}$${\mathit{D}}_{3}$ as well as for fine-structure mixing within the $^{3}$D multiplet were obtained by fitting the numerical solution of a seven-state system of rate equations including diffusion to the experimental data. We compare our results to experimental findings for other alkaline earth metals and report an improved value of the lifetime of the 6s6p $^{3}$${\mathit{P}}_{1}$ state of barium.

DOI
10.1103/physreva.52.2120

Related papers

Excitation transfer among, and quenching of, the barium 6s5d 3 DJ metastable levels due to collisions with argon, nitrogen, and barium perturbers

E. Ehrlacher, John Huennekens

We describe a set of experiments that investigate excitation transfer among the barium 6s5d $^{3}$${\mathit{D}}_{\mathit{J}}$ metastable levels due to collisions with argon perturber atoms, and quenching of atoms in these levels by nitrogen perturber molecules. The metastable levels were populated through optical pumping of the 6${\mathit{s}}^{2}$ $^{1}$${\mathit{S}}_{0}$\ensuremath{\rightarrow}6s6p $^{3}$${\mathit{P}}_{1}^{\mathit{o}}$ intercombination transition with a pulsed laser, followed by stimulated emission or stimulated Raman scattering into the 6s5d $^{3}$${\mathit{D}}_{1,2}$ levels. Collisional mixing then distributed population throughout the $^{3}$${\mathit{D}}_{\mathit{J}}$ levels. Time-dependent absorption coefficients were obtained by measuring the transmission of a weak cw probe laser beam (after the pulsed laser fired) at several perturber number densities. Argon buffer gas was used to investigate fine-structure mixing, and nitrogen was used to study quenching. The time-dependent absorption coefficients were fitted to appropriate fitting functions, obtained by solving the set of coupled rate equations used to model the time evolution of the metastable level populations. The buildup rates of the initially unpopulated $^{3}$${\mathit{D}}_{3}$ and underpopulated $^{3}$${\mathit{D}}_{1}$ levels were used to determine the collisional mixing rates, while the measured decay rates of the $^{3}$${\mathit{D}}_{\mathit{J}}$ level populations yielded the quenching rates. From plots of buildup rates versus argon number density for the $^{3}$${\mathit{D}}_{1,3}$ states, we were able to determine four of the six fine-structure mixing rate coefficients ${\mathit{k}}_{\mathit{i}\mathit{j}}$.The results are ${\mathit{k}}_{12}$=(1.71\ifmmode\pm\else\textpm\fi{}0.18), ${\mathit{k}}_{21}$=(1.39\ifmmode\pm\else\textpm\fi{}0.13), ${\mathit{k}}_{23}$=(1.42\ifmmode\pm\else\textpm\fi{}0.13), and ${\mathit{k}}_{32}$=(1.92\ifmmode\pm\else\textpm\fi{}0.16)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}13}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$. The experiment is not sensitive to the values of ${\mathit{k}}_{13}$ and ${\mathit{k}}_{31}$. Estimated rate coefficients for excitation transfer among the $^{3}$${\mathit{D}}_{\mathit{J}}$ levels due to collisions with barium atoms are ${\mathit{k}}_{21}^{\mathrm{Ba}}$=1.3\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ and ${\mathit{k}}_{23}^{\mathrm{Ba}}$=5.8\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$. A plot of the population decay rates versus ${\mathrm{N}}_{2}$ number density for each of the three metastable levels yielded the average nitrogen quenching rate coefficient ${\mathit{k}}_{\mathit{q}}$=(3.14\ifmmode\pm\else\textpm\fi{}0.19)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}11}$ ${\mathrm{cm}}^{3}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$.

Physical Review A•Dec 1, 1994•26 citations

Diffusion of barium atoms in the 6s5d 3 DJ metastable levels and the 6 s2 1 S0 ground state through noble-gas perturbers

R. K. Namiotka, E. Ehrlacher, J. Sagle +5 more

We describe a set of experiments that investigate diffusion of barium 6s5d${\mathrm{}}^{3}$${\mathit{D}}_{\mathit{J}}$ metastable level and 6${\mathit{s}}^{2}$${\mathrm{}}^{1}$${\mathit{S}}_{0}$ ground-state atoms through the noble gases: He, Ne, Ar, Kr, and Xe. The barium metastable levels were populated through optical pumping of the 6${\mathit{s}}^{2}$${\mathrm{}}^{1}$${\mathit{S}}_{0}$\ensuremath{\rightarrow}6s6p${\mathrm{}}^{3}$${\mathit{P}}_{1}^{\mathit{o}}$ intercombination transition with a pulsed laser, followed by spontaneous or stimulated emission into the 6s5d${\mathrm{}}^{3}$${\mathit{D}}_{1,2}$ levels. Collisional mixing then distributed population throughout the 6s5d${\mathrm{}}^{3}$${\mathit{D}}_{\mathit{J}}$ levels. A weak narrow-band cw laser was tuned to appropriate transitions to probe the spatial distribution of metastable level atoms, as well as the hole created in the ground-state spatial distribution, by the pulsed laser. Time-dependent absorption coefficients were obtained by measuring the transmission of the probe laser at several different pump-probe spatial separations. From these absorption data, spatial number density profiles were mapped out for various times following the firing of the pump laser. These density profiles were used to determine the diffusion coefficient for each state at a particular buffer-gas pressure and temperature. From these pressure- and temperature-dependent diffusion coefficients D, we determined the thermally averaged diffusion cross sections ${\mathrm{\ensuremath{\sigma}}}_{\mathit{D}}$(6s5d${\mathrm{}}^{3}$${\mathit{D}}_{\mathit{J}}$) and ${\mathrm{\ensuremath{\sigma}}}_{\mathit{D}}$(6${\mathit{s}}^{2}$${\mathrm{}}^{1}$${\mathit{S}}_{0}$) for the metastable and ground-state atoms diffusing through the noble gases, respectively. We also report values for the scaled standard diffusion coefficients ${\mathit{D}}_{0}$. Our experimental values of the thermally averaged diffusion cross sections ${\mathrm{\ensuremath{\sigma}}}_{\mathit{D}}$(6s5d${\mathrm{}}^{3}$${\mathit{D}}_{\mathit{J}}$) and ${\mathrm{\ensuremath{\sigma}}}_{\mathit{D}}$(6${\mathit{s}}^{2}$${\mathrm{}}^{1}$${\mathit{S}}_{0}$) for the barium-helium system are compared with values calculated from published, theoretical barium-helium potentials and the agreement is excellent. \textcopyright{} 1996 The American Physical Society.

Physical Review A•Jul 1, 1996•16 citations

Collisional Deactivation of Ba 5d7p 3D1 by Noble Gases

John E. Smedley, Sarah K. Coulter, Edward J. Felton +1 more

Collisional deactivation of the 5d7p (3)D1 state of Ba by noble gases is studied by time- and wavelength-resolved fluorescence techniques. A pulsed, frequency-doubled dye laser at 273.9 nm excites the 5d7p (3)D1 level from the ground state, and fluorescence at 364.1 and 366.6 nm from the 5d7p (3)D1 --> 6s5d (3)D1 and 5d7p (3)D1 --> 6s5d (3)D2 transitions, respectively, is monitored in real time to obtain the deactivation rate constants. At 835 K these rate constants are as follows: He, (1.69 +/- 0.08) x 10(-9) cm(3) s(-1); Ne, (3.93 +/- 0.14) x 10(-10) cm(3) s(-1); Ar, (4.53 +/- 0.15) x 10(-10) cm(3) s(-1); Kr, (4.64 +/- 0.13) x 10(-10) cm(3) s(-1); Xe, (5.59 +/- 0.22) x 10(-10) cm(3) s(-1). From time-resolved 5d7p (3)D1 emission in the absence of noble gas and from the intercepts of the quenching plots, the lifetime of this state is determined to be 100 +/- 1 ns. Using time- and wavelength-resolved Ba emission with a low background pressure of noble gas, radiative lifetimes of several near-resonant states are determined from the exponential rise of the fluorescence signals. These results are as follows: 5d6d (3)D3, 28 +/- 3 ns; 5d7p (3)P1, 46 +/- 2 ns; 5d6d (3)G3, 21.5 +/- 0.8 ns; 5d7p (3)F3, 48 +/- 1 ns. Integrated fluorescence signals are used to infer the relative rate constants for population transfer from the 5d7p (3)D1 state to eleven near-resonant fine structure states.

The Journal of Physical Chemistry A•Jul 17, 2008•5 citations

THE 6s5d 1 D2 ! 6s5d 3 DJ EXCITATION ENERGY TRANSFER IN BARIUM INDUCED BY COLLISIONS WITH He, Ar AND Xe ATOMS

Cedomil Vadla, Vlasta Horvatić

the description of the population and depopulation processes of the Ba metastable states in noble gas atmosphere. The analysis of the experimental results, within the assumed model, yields the following cross-section values for the investigated

FizA•Jan 1, 1995•3 citations

Energy-pooling collisions in barium

Jonathan Andrew Neuman, Alan C. Gallagher, J. Cooper

Rate coefficients for energy-pooling collisions between low-lying excited states of Ba have been measured. The 6s6p${(}^{3}$${\mathit{P}}_{1}$) level in Ba is pumped by a cw diode laser, and radiative decay and collisions with buffer-gas atoms also populate the 5d6s${(}^{1}$D) and 5d6s${(}^{3}$D) metastable levels. The densities of these low-lying excited states are measured by the absorption of lines from a Ba hollow-cathode lamp, and the states populated by energy-pooling collisions are studied by comparing their fluorescence intensity to that of the laser-excited level. The rate coefficients are on the order of gas-kinetic rates, and they are not strongly dependent on energy defect, spin changes, or angular-momentum changes.

Physical Review A•Aug 1, 1994•20 citations

Collisional relaxation in 5(2)P potassium atoms.

R. W. Berends

Collisional excitation transfer and relaxation of K 5$\\sp2$P atoms in collisions with noble gases, as well as the radiative lifetimes of the K 5P, 6P and 7P fine-structure states have been investigated by methods of atomic fluorescence spectroscopy. Potassium vapour was mixed in a cell with a noble gas and selectively excited by pulsed dye-laser radiation to the 5$\\sp2$P$\\sb{1\\over2}$ or the 5$\\sp2$P$\\sb{3\\over 2}$ state in zero magnetic field and to the 5$\\sp2$P$\\sb{{1\\over 2}-{1\\over 2}}$ or the 5$\\sp2$P$\\sb{{3\\over 2}-{3\\over 2}}$ Zeeman substate in a field of 70 kG. Interferometric analysis of the fluorescence emitted from the directly (optically) excited state and that emitted from the collisionally populated states allowed the determination of the fine-structure mixing cross sections for collisions with He, Ne, Ar, Kr and Xe in zero magnetic field. Excitation transfer between Zeeman substates was investigated for collisions between the selectively excited 5P atoms and He, Ne and Ar atoms, allowing the determination of the multipole relaxation (depolarization) cross sections for dipole, quadrupole and octupole decay, as well as the Zeeman and fine-structure mixing cross sections and orientation transfer cross sections. A comparison of theoretical calculations with the experimental data has been made and the rate equations governing multipole relaxation and including effects due to strong fine-structure mixing on the multipole relaxation, have been described in detail. The radiative lifetimes of the individual fine-structure components of the K 5P, 6P and 7P states have been determined experimentally by means of time-resolved laser-induced fluorescence techniques. These data are compared with numerous theoretical calculations and the available experimental values.Dept. of Physics. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1988 .B474. Source: Dissertation Abstracts International, Volume: 49-04, Section: B, page: 1223. Thesis (Ph.D.)--University of Windsor (Canada), 1988.

•Jan 1, 1988•0 citations
We present a time resolved study of excitation transfer processes between the low lying excited states of barium (6s6p ^{3}$${\mathit{P}}_{\mathit{J}}, 6s5d ^{1}$${\mathit{D}}_{2}, 6s5d ^{3}$${\mathit{D}}_{\mathit{J}}) induced by collisions with noble gases. The transient excited state populations have been measured by means of fluorescence and absorption spectroscopy. Cross sections for spin-changing collisions from ^{3}$${\mathit{P}}_{1} to ^{1}$${\mathit{D}}_{2} and from ^{1}$${\mathit{D}}_{2} to ^{3}$${\mathit{D}}_{3} as well as for fine-structure mixing within the 3^{3}3D multiplet were obtained by fitting the numerical solution of a seven-state system of rate equations including diffusion to the experimental data. We compare our results to experimental findings for other alkaline earth metals and report an improved value of the lifetime of the 6s6p ^{3}$${\mathit{P}}_{1} state of barium.
We describe a set of experiments that investigate excitation transfer among the barium 6s5d 3^{3}3DJ{\mathit{D}}_{\mathit{J}}DJ​ metastable levels due to collisions with argon perturber atoms, and quenching of atoms in these levels by nitrogen perturber molecules. The metastable levels were populated through optical pumping of the 6s2{\mathit{s}}^{2}s2 1^{1}1S0{\mathit{S}}_{0}S0​\ensuremath{\rightarrow}6s6p 3^{3}3P1o{\mathit{P}}_{1}^{\mathit{o}}P1o​ intercombination transition with a pulsed laser, followed by stimulated emission or stimulated Raman scattering into the 6s5d 3^{3}3D1,2{\mathit{D}}_{1,2}D1,2​ levels. Collisional mixing then distributed population throughout the 3^{3}3DJ{\mathit{D}}_{\mathit{J}}DJ​ levels. Time-dependent absorption coefficients were obtained by measuring the transmission of a weak cw probe laser beam (after the pulsed laser fired) at several perturber number densities. Argon buffer gas was used to investigate fine-structure mixing, and nitrogen was used to study quenching. The time-dependent absorption coefficients were fitted to appropriate fitting functions, obtained by solving the set of coupled rate equations used to model the time evolution of the metastable level populations. The buildup rates of the initially unpopulated 3^{3}3D3{\mathit{D}}_{3}D3​ and underpopulated 3^{3}3D1{\mathit{D}}_{1}D1​ levels were used to determine the collisional mixing rates, while the measured decay rates of the 3^{3}3DJ{\mathit{D}}_{\mathit{J}}DJ​ level populations yielded the quenching rates. From plots of buildup rates versus argon number density for the 3^{3}3D1,3{\mathit{D}}_{1,3}D1,3​ states, we were able to determine four of the six fine-structure mixing rate coefficients kij{\mathit{k}}_{\mathit{i}\mathit{j}}kij​.The results are k12{\mathit{k}}_{12}k12​=(1.71\ifmmode\pm\else\textpm\fi{}0.18), k21{\mathit{k}}_{21}k21​=(1.39\ifmmode\pm\else\textpm\fi{}0.13), k23{\mathit{k}}_{23}k23​=(1.42\ifmmode\pm\else\textpm\fi{}0.13), and k32{\mathit{k}}_{32}k32​=(1.92\ifmmode\pm\else\textpm\fi{}0.16)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}13}$ cm3{\mathrm{cm}}^{3}cm3 ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$. The experiment is not sensitive to the values of k13{\mathit{k}}_{13}k13​ and k31{\mathit{k}}_{31}k31​. Estimated rate coefficients for excitation transfer among the 3^{3}3DJ{\mathit{D}}_{\mathit{J}}DJ​ levels due to collisions with barium atoms are k21Ba{\mathit{k}}_{21}^{\mathrm{Ba}}k21Ba​=1.3\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$ cm3{\mathrm{cm}}^{3}cm3 ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ and k23Ba{\mathit{k}}_{23}^{\mathrm{Ba}}k23Ba​=5.8\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$ cm3{\mathrm{cm}}^{3}cm3 ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$. A plot of the population decay rates versus N2{\mathrm{N}}_{2}N2​ number density for each of the three metastable levels yielded the average nitrogen quenching rate coefficient kq{\mathit{k}}_{\mathit{q}}kq​=(3.14\ifmmode\pm\else\textpm\fi{}0.19)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}11}$ cm3{\mathrm{cm}}^{3}cm3 ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$.
We describe a set of experiments that investigate diffusion of barium 6s5d3{\mathrm{}}^{3}3DJ{\mathit{D}}_{\mathit{J}}DJ​ metastable level and 6s2{\mathit{s}}^{2}s21{\mathrm{}}^{1}1S0{\mathit{S}}_{0}S0​ ground-state atoms through the noble gases: He, Ne, Ar, Kr, and Xe. The barium metastable levels were populated through optical pumping of the 6s2{\mathit{s}}^{2}s21{\mathrm{}}^{1}1S0{\mathit{S}}_{0}S0​\ensuremath{\rightarrow}6s6p3{\mathrm{}}^{3}3P1o{\mathit{P}}_{1}^{\mathit{o}}P1o​ intercombination transition with a pulsed laser, followed by spontaneous or stimulated emission into the 6s5d3{\mathrm{}}^{3}3D1,2{\mathit{D}}_{1,2}D1,2​ levels. Collisional mixing then distributed population throughout the 6s5d3{\mathrm{}}^{3}3DJ{\mathit{D}}_{\mathit{J}}DJ​ levels. A weak narrow-band cw laser was tuned to appropriate transitions to probe the spatial distribution of metastable level atoms, as well as the hole created in the ground-state spatial distribution, by the pulsed laser. Time-dependent absorption coefficients were obtained by measuring the transmission of the probe laser at several different pump-probe spatial separations. From these absorption data, spatial number density profiles were mapped out for various times following the firing of the pump laser. These density profiles were used to determine the diffusion coefficient for each state at a particular buffer-gas pressure and temperature. From these pressure- and temperature-dependent diffusion coefficients D, we determined the thermally averaged diffusion cross sections ${\mathrm{\ensuremath{\sigma}}}_{\mathit{D}}$(6s5d3{\mathrm{}}^{3}3DJ{\mathit{D}}_{\mathit{J}}DJ​) and ${\mathrm{\ensuremath{\sigma}}}_{\mathit{D}}$(6s2{\mathit{s}}^{2}s21{\mathrm{}}^{1}1S0{\mathit{S}}_{0}S0​) for the metastable and ground-state atoms diffusing through the noble gases, respectively. We also report values for the scaled standard diffusion coefficients D0{\mathit{D}}_{0}D0​. Our experimental values of the thermally averaged diffusion cross sections ${\mathrm{\ensuremath{\sigma}}}_{\mathit{D}}$(6s5d3{\mathrm{}}^{3}3DJ{\mathit{D}}_{\mathit{J}}DJ​) and ${\mathrm{\ensuremath{\sigma}}}_{\mathit{D}}$(6s2{\mathit{s}}^{2}s21{\mathrm{}}^{1}1S0{\mathit{S}}_{0}S0​) for the barium-helium system are compared with values calculated from published, theoretical barium-helium potentials and the agreement is excellent. \textcopyright{} 1996 The American Physical Society.
Collisional deactivation of the 5d7p (3)D1 state of Ba by noble gases is studied by time- and wavelength-resolved fluorescence techniques. A pulsed, frequency-doubled dye laser at 273.9 nm excites the 5d7p (3)D1 level from the ground state, and fluorescence at 364.1 and 366.6 nm from the 5d7p (3)D1 --> 6s5d (3)D1 and 5d7p (3)D1 --> 6s5d (3)D2 transitions, respectively, is monitored in real time to obtain the deactivation rate constants. At 835 K these rate constants are as follows: He, (1.69 +/- 0.08) x 10(-9) cm(3) s(-1); Ne, (3.93 +/- 0.14) x 10(-10) cm(3) s(-1); Ar, (4.53 +/- 0.15) x 10(-10) cm(3) s(-1); Kr, (4.64 +/- 0.13) x 10(-10) cm(3) s(-1); Xe, (5.59 +/- 0.22) x 10(-10) cm(3) s(-1). From time-resolved 5d7p (3)D1 emission in the absence of noble gas and from the intercepts of the quenching plots, the lifetime of this state is determined to be 100 +/- 1 ns. Using time- and wavelength-resolved Ba emission with a low background pressure of noble gas, radiative lifetimes of several near-resonant states are determined from the exponential rise of the fluorescence signals. These results are as follows: 5d6d (3)D3, 28 +/- 3 ns; 5d7p (3)P1, 46 +/- 2 ns; 5d6d (3)G3, 21.5 +/- 0.8 ns; 5d7p (3)F3, 48 +/- 1 ns. Integrated fluorescence signals are used to infer the relative rate constants for population transfer from the 5d7p (3)D1 state to eleven near-resonant fine structure states.
Rate coefficients for energy-pooling collisions between low-lying excited states of Ba have been measured. The 6s6p(3{(}^{3}(3P1{\mathit{P}}_{1}P1​) level in Ba is pumped by a cw diode laser, and radiative decay and collisions with buffer-gas atoms also populate the 5d6s(1{(}^{1}(1D) and 5d6s(3{(}^{3}(3D) metastable levels. The densities of these low-lying excited states are measured by the absorption of lines from a Ba hollow-cathode lamp, and the states populated by energy-pooling collisions are studied by comparing their fluorescence intensity to that of the laser-excited level. The rate coefficients are on the order of gas-kinetic rates, and they are not strongly dependent on energy defect, spin changes, or angular-momentum changes.
Collisional excitation transfer and relaxation of K 5sp2\\sp2sp2P atoms in collisions with noble gases, as well as the radiative lifetimes of the K 5P, 6P and 7P fine-structure states have been investigated by methods of atomic fluorescence spectroscopy. Potassium vapour was mixed in a cell with a noble gas and selectively excited by pulsed dye-laser radiation to the 5sp2\\sp2sp2Psb1over2\\sb{1\\over2}sb1over2 or the 5sp2\\sp2sp2Psb3over2\\sb{3\\over 2}sb3over2 state in zero magnetic field and to the 5sp2\\sp2sp2Psb1over2−1over2\\sb{{1\\over 2}-{1\\over 2}}sb1over2−1over2 or the 5sp2\\sp2sp2Psb3over2−3over2\\sb{{3\\over 2}-{3\\over 2}}sb3over2−3over2 Zeeman substate in a field of 70 kG. Interferometric analysis of the fluorescence emitted from the directly (optically) excited state and that emitted from the collisionally populated states allowed the determination of the fine-structure mixing cross sections for collisions with He, Ne, Ar, Kr and Xe in zero magnetic field. Excitation transfer between Zeeman substates was investigated for collisions between the selectively excited 5P atoms and He, Ne and Ar atoms, allowing the determination of the multipole relaxation (depolarization) cross sections for dipole, quadrupole and octupole decay, as well as the Zeeman and fine-structure mixing cross sections and orientation transfer cross sections. A comparison of theoretical calculations with the experimental data has been made and the rate equations governing multipole relaxation and including effects due to strong fine-structure mixing on the multipole relaxation, have been described in detail. The radiative lifetimes of the individual fine-structure components of the K 5P, 6P and 7P states have been determined experimentally by means of time-resolved laser-induced fluorescence techniques. These data are compared with numerous theoretical calculations and the available experimental values.Dept. of Physics. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1988 .B474. Source: Dissertation Abstracts International, Volume: 49-04, Section: B, page: 1223. Thesis (Ph.D.)--University of Windsor (Canada), 1988.