Physical Review A

Angular distribution of electrons from two-photon ionization of Ti atoms

S. A. Edelstein, Melissa Lambropoulos, John A. Duncanson, R. Stephen Berry

Published Jun 1, 1974• 32 citations

Abstract

Titanium atoms are excited by light from a nitrogen laser from the $a^{3}F_{4}$ state, near the ground state, through the $x^{3}G_{5}$ state, to become $^{4}F$ ions plus free electrons. The angular distribution of photoelectrons from the process gives limits on the ratio of amplitudes for transitions from the intermediate $4p$ orbital to the final continuum $s$ and $d$ channels. The total number of photoelectrons indicates that the total ionization cross section for the $^{3}G_{5}$ state is 1\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}18}$ ${\mathrm{cm}}^{2}$. While the method can, in principle, provide relaxation times for angular momentum reorientation (an application of the methods of perturbed angular correlations in atomic processes), the present measurements have been carried out under conditions in which no relaxation occurs.

DOI: 10.1103/physreva.9.2459

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Angular Distributions from Resonant Two-Photon Ionization

Melissa Lambropoulos, R. Stephen Berry

Physical Review AAug 1, 197336 citations

Two-photon ionization of many-electron atoms

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Jan 1, 20200 citations

Multiphoton ionization of the calcium atom by linearly and circularly polarized laser fields

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Photoelectron angular distributions for two-photon ionization of atomic rubidium

Yi-Yian Yin, Daniel S. Elliott

In this paper we report measurements of photoelectron angular distributions for two-photon ionization of atomic rubidium. These measurements are carried out over a range of laser wavelengths from 591 to 532 nm. Relative cross sections for the various photoionization channels and continuum-wave-function phase differences are derived from the data. These phase differences are not in good agreement with calculations of phase differences based on quantum-defect data and Coulomb phase shifts.

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Physical Review AJan 1, 19888 citations

Physical Review A

Angular distribution of electrons from two-photon ionization of Ti atoms

S. A. Edelstein, Melissa Lambropoulos, John A. Duncanson, R. Stephen Berry

Published Jun 1, 1974• 32 citations

Publisher

Abstract

Titanium atoms are excited by light from a nitrogen laser from the

a^{3}F_{4}

state, near the ground state, through the

x^{3}G_{5}

state, to become

^{4}F

ions plus free electrons. The angular distribution of photoelectrons from the process gives limits on the ratio of amplitudes for transitions from the intermediate

4p

orbital to the final continuum

s

and

d

channels. The total number of photoelectrons indicates that the total ionization cross section for the

^{3}G_{5}

state is 1\ifmmode\times\else\texttimes\fi{}

{10}^{\ensuremath{-}18}

{\mathrm{cm}}^{2}

. While the method can, in principle, provide relaxation times for angular momentum reorientation (an application of the methods of perturbed angular correlations in atomic processes), the present measurements have been carried out under conditions in which no relaxation occurs.

DOI: 10.1103/physreva.9.2459

Related papers

Angular Distributions from Resonant Two-Photon Ionization

Melissa Lambropoulos, R. Stephen Berry

A general theory is developed to treat two-photon ionization through a single intermediate state in which an arbitrary degree of relaxation may occur. The method is set up to probe the parameters governing the relaxation, by determination of the angular distribution of photoelectrons. The method is applied to the ionization of Na atoms, through the $3p^{2}P_{\frac{1}{2}}$ and $3p^{2}P_{\frac{3}{2}}$ intermediate states.A general theory is developed to treat two-photon ionization through a single intermediate state in which an arbitrary degree of relaxation may occur. The method is set up to probe the parameters governing the relaxation, by determination of the angular distribution of photoelectrons. The method is applied to the ionization of Na atoms, through the $3p^{2}P_{\frac{1}{2}}$ and $3p^{2}P_{\frac{3}{2}}$ intermediate states.

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Two-photon ionization of many-electron atoms

J. Hofbrucker

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Jan 1, 20200 citations

Multiphoton ionization of the calcium atom by linearly and circularly polarized laser fields

Gabriela Buică, Takashi Nakajima

We theoretically study multiphoton ionization of the Ca atom irradiated by the second (photon energy $3.1$ eV) and third (photon energy 4.65 eV) harmonics of Ti:sapphire laser pulses (photon energy $1.55$ eV). Because of the dense energy level structure the second and third harmonics of a Ti:sapphire laser are nearly single-photon resonant with the $4s4p$ ${}^{1}{P}^{o}$ and $4s5p$ ${}^{1}{P}^{o}$ states, respectively. Although two-photon ionization takes place through the near-resonant intermediate states with the same symmetry in both cases, it turns out that there are significant differences between them. The photoelectron energy spectra exhibit the absence or presence of substructures. More interestingly, the photoelectron angular distributions clearly show that the main contribution to the ionization processes by the third harmonic arises from the far-off-resonant $4s4p$ ${}^{1}{P}^{o}$ state rather than the near-resonant $4s5p$ ${}^{1}{P}^{o}$ state. These findings can be attributed to the fact that the dipole moment for the $4{s}^{2}$ ${}^{1}{S}^{e}\ensuremath{-}4s5p$ ${}^{1}{P}^{o}$ transition is much smaller than that for the $4{s}^{2}$ ${}^{1}{S}^{e}\ensuremath{-}4s4p$ ${}^{1}{P}^{o}$ transition.We theoretically study multiphoton ionization of the Ca atom irradiated by the second (photon energy $3.1$ eV) and third (photon energy 4.65 eV) harmonics of Ti:sapphire laser pulses (photon energy $1.55$ eV). Because of the dense energy level structure the second and third harmonics of a Ti:sapphire laser are nearly single-photon resonant with the $4s4p$ ${}^{1}{P}^{o}$ and $4s5p$ ${}^{1}{P}^{o}$ states, respectively. Although two-photon ionization takes place through the near-resonant intermediate states with the same symmetry in both cases, it turns out that there are significant differences between them. The photoelectron energy spectra exhibit the absence or presence of substructures. More interestingly, the photoelectron angular distributions clearly show that the main contribution to the ionization processes by the third harmonic arises from the far-off-resonant $4s4p$ ${}^{1}{P}^{o}$ state rather than the near-resonant $4s5p$ ${}^{1}{P}^{o}$ state. These findings can be attributed to the fact that the dipole moment for the $4{s}^{2}$ ${}^{1}{S}^{e}\ensuremath{-}4s5p$ ${}^{1}{P}^{o}$ transition is much smaller than that for the $4{s}^{2}$ ${}^{1}{S}^{e}\ensuremath{-}4s4p$ ${}^{1}{P}^{o}$ transition.

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Yi-Yian Yin, Daniel S. Elliott

Physical Review AApr 1, 19939 citations

Multiphoton ionization of Ba atoms with photoelectron spectroscopy

A. Yu. Elizarov

An experimental and theoretically study is performed of the angular photoelectron distribution for three-photon ionization of Ba atoms through the 2(omega) -excited intermediate state 6p2 (1So) and the auto- ionized state 6p8s(3P1). Rotation of the polarization plane of dye-laser radiation allowed us to investigate the photoelectron angular distribution. Electrons were counted with the help of a time-of-flight electron spectrometer. Employing the density-matrix formalism, expressions have been obtained for angular dependence of the differential ionizations probability. Possible experiments are discussed.An experimental and theoretically study is performed of the angular photoelectron distribution for three-photon ionization of Ba atoms through the 2(omega) -excited intermediate state 6p2 (1So) and the auto- ionized state 6p8s(3P1). Rotation of the polarization plane of dye-laser radiation allowed us to investigate the photoelectron angular distribution. Electrons were counted with the help of a time-of-flight electron spectrometer. Employing the density-matrix formalism, expressions have been obtained for angular dependence of the differential ionizations probability. Possible experiments are discussed.

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Multiphoton ionization of cesium via quadrupole transitions: Photoelectron angular distributions and polarization effects on total ionization rates

A. Lyras, Bo-nian Dai, Xian Tang +5 more

We report measurements of photoelectron angular distributions via electric quadrupole transitions in cesium atoms using multiphoton excitation techniques. Experimental results are presented for the cases of one-photon resonant, two-photon ionization via the 6d ${\mathrm{}}^{2}$ ${D}_{3/2}$ and 6d ${\mathrm{}}^{2}$ ${D}_{5/2}$ electric quadrupole transitions and for one-photon resonant, three-photon ionization via the 5d ${\mathrm{}}^{2}$ ${\mathrm{D}}_{3/2}$ and 5d ${\mathrm{}}^{2}$ ${D}_{5/2}$ transitions. The ratios of the total ionization rates for linearly and circularly polarized light have also been measured for the 6d ${\mathrm{}}^{2}$ ${\mathrm{D}}_{3/2}$ and 6d ${\mathrm{}}^{2}$ ${D}_{5/2}$ states. A theoretical analysis and detailed comparison with the experimental results are given.We report measurements of photoelectron angular distributions via electric quadrupole transitions in cesium atoms using multiphoton excitation techniques. Experimental results are presented for the cases of one-photon resonant, two-photon ionization via the 6d ${\mathrm{}}^{2}$${D}_{3/2}$ and 6d ${\mathrm{}}^{2}$${D}_{5/2}$ electric quadrupole transitions and for one-photon resonant, three-photon ionization via the 5d ${\mathrm{}}^{2}$ ${\mathrm{D}}_{3/2}$ and 5d ${\mathrm{}}^{2}$${D}_{5/2}$ transitions. The ratios of the total ionization rates for linearly and circularly polarized light have also been measured for the 6d ${\mathrm{}}^{2}$${\mathrm{D}}_{3/2}$ and 6d ${\mathrm{}}^{2}$${D}_{5/2}$ states. A theoretical analysis and detailed comparison with the experimental results are given.

Physical Review AJan 1, 19888 citations

Titanium atoms are excited by light from a nitrogen laser from the

a^{3}F_{4}

state, near the ground state, through the

x^{3}G_{5}

state, to become

^{4}F

ions plus free electrons. The angular distribution of photoelectrons from the process gives limits on the ratio of amplitudes for transitions from the intermediate

4p

orbital to the final continuum

s

and

d

channels. The total number of photoelectrons indicates that the total ionization cross section for the

^{3}G_{5}

state is 1\ifmmode\times\else\texttimes\fi{}

{10}^{\ensuremath{-}18}

{\mathrm{cm}}^{2}

3p^{2}P_{\frac{1}{2}}

and

3p^{2}P_{\frac{3}{2}}

intermediate states.

We theoretically study multiphoton ionization of the Ca atom irradiated by the second (photon energy

3.1

eV) and third (photon energy 4.65 eV) harmonics of Ti:sapphire laser pulses (photon energy

1.55

eV). Because of the dense energy level structure the second and third harmonics of a Ti:sapphire laser are nearly single-photon resonant with the

4s4p

{}^{1}{P}^{o}

and

4s5p

{}^{1}{P}^{o}

states, respectively. Although two-photon ionization takes place through the near-resonant intermediate states with the same symmetry in both cases, it turns out that there are significant differences between them. The photoelectron energy spectra exhibit the absence or presence of substructures. More interestingly, the photoelectron angular distributions clearly show that the main contribution to the ionization processes by the third harmonic arises from the far-off-resonant

4s4p

{}^{1}{P}^{o}

state rather than the near-resonant

4s5p

{}^{1}{P}^{o}

state. These findings can be attributed to the fact that the dipole moment for the

4{s}^{2}

${}^{1}{S}^{e}\ensuremath{-}4s5p$

{}^{1}{P}^{o}

transition is much smaller than that for the

4{s}^{2}

${}^{1}{S}^{e}\ensuremath{-}4s4p$

{}^{1}{P}^{o}

transition.

{\mathrm{}}^{2}

{D}_{3/2}

and 6d

{\mathrm{}}^{2}

{D}_{5/2}

electric quadrupole transitions and for one-photon resonant, three-photon ionization via the 5d

{\mathrm{}}^{2}

{\mathrm{D}}_{3/2}

and 5d

{\mathrm{}}^{2}

{D}_{5/2}

transitions. The ratios of the total ionization rates for linearly and circularly polarized light have also been measured for the 6d

{\mathrm{}}^{2}

{\mathrm{D}}_{3/2}

and 6d

{\mathrm{}}^{2}

{D}_{5/2}

states. A theoretical analysis and detailed comparison with the experimental results are given.