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

The Journal of Chemical Physics

Femtosecond photon echo measurements of electronic coherence relaxation between the X(1Σg+) and B(3Π0u+) states of I2 in the presence of He, Ar, N2, O2, C3H8

Matthew Comstock, Vadim V. Lozovoy, Marcos M. Dantus

Published Sep 18, 2003• 13 citations
Publisher

Abstract

Photon echo and reverse transient grating measurements of the loss of electronic coherence for molecular iodine are presented. Systematic measurements of the coherence decay rate were made as a function of buffer gas. From the dependence of decay rate on numerical density, we calculated experimental cross sections of decoherence. These values range from 135 Å2 for helium to 1170 Å2 for I2. We find Lennard-Jones parameters for the long-range interactions responsible for decoherence which can be modeled by dispersion forces.

DOI
10.1063/1.1603739

Related papers

Femtosecond photon echo measurements of electronic coherence relaxation of I2 in the presence of He, Ar, N2, O2, C3H8

Vadim V. Lozovoy, Matthew Comstock, Igor Pastirk +1 more

Elsevier eBooks•Jan 1, 2004•0 citations

Time-resolved CARS measurements of the vibrational decoherence of I2 isolated in an Ar matrix

Michael Karavitis, D. Segale, Z. Bihary +2 more

Time-resolved coherent anti-Stokes Raman scattering is applied to prepare and interrogate vibrational coherences on the ground electronic surface of molecular iodine isolated in Ar matrices. The coherence decay time shows a linear dependence on vibrational quantum numbers for v=3–15. The temperature dependence of decoherence rates is negligible for v<7 in the experimental range T=18–32 K. For a v=13, 14 superposition, the temperature dependence indicates dephasing by a 66 cm−1 pseudo-local phonon, just outside the Debye edge of the solid. The accuracy of the data is limited due to two-photon induced dissociation of the molecule, a process which is characterized using polarized fields. The T→0 limit of dephasing is discussed.

Low Temperature Physics•Sep 1, 2003•23 citations

Time resolved coherent anti-Stokes Raman scattering of I2 isolated in matrix argon: Vibrational dynamics on the ground electronic state

Michael Karavitis, R. Zadoyan, Vartkess Ara Apkarian

Time-resolved, electronically resonant, coherent anti-Stokes Raman scattering is used to prepare and interrogate vibronic coherences of molecular iodine in matrix Ar. Coherences that involve evolution on the excited B(3Π0u) state, first- and third-order coherences, decay in less than one vibrational period (τ<300 fs). In contrast, as many as 200 vibrational periods of motion can be observed for Raman-prepared wave packets consisting of zero-phonon vibrational superpositions on the ground electronic state (second-order coherence). Packets consisting of v=4, 5 and v=3, 4, 5 on the X(1Σg) state decay with a half-life of 10±1 ps at 31 K, allowing a more accurate measure of vibrational level spacings and decoherence time than has been possible in frequency domain. The harmonic frequency of the molecule is reduced by 1.5 cm−1 (0.7%) in the matrix. The lack of recurrence in the excited electronic state ensures that the resonant anti-Stokes scattering arises only from the negative momentum component of the Raman packet. This momentum filter, which should be ubiquitous in condensed media, leads to a signal with deeper modulation than in the gas phase.

The Journal of Chemical Physics•Mar 1, 2001•52 citations

Coherent transients in gases

Н. Н. Рубцова, Гольдорт Вениамин Гершевич, В. Н. Ищенко +5 more

A great variety of coherent transient processes in atomic and molecular gases is investigated. The degeneracy with respect to magnetic sublevels, which is typical of working levels of atomic and molecular transitions in gases, leads to new phenomena. In particular, the non-Faraday rotation of the coherent-response polarization vector at the 0 ↔ 1 transition is investigated in the presence of the longitudinal magnetic field in the 174 Yb vapor for both photon echo and stimulated photon echo. A specific relaxation channel that involves the depolarizing collisions emerges in a gas due to the degeneracy of working levels. Such collisions are especially important for atoms and are also observed in molecules. The anisotropy of the depolarizing collisions leads to a new phenomenon of the collision photon echo, which is experimentally demonstrated for the 0 ↔ 1 transition in the 174 Yb mixtures with atomic buffers. The velocity-dependent relaxation rates are observed for various coherent phenomena in molecular gases. The coherent control of a few coherent transient processes is implemented.

Laser Physics•Jul 1, 2011•3 citations

Collisional Relaxation of Backward Photon Echo in Molecular Sodium

修治 浅香, Hirofumi Yamada, Hiroki Nakatsuka +1 more

Backward photon echo and its decay were observed in the X Σ - A Σ transition of Na 2 undergoing collisions with Ar buffer gas. By using the quantum mechanical transport equation, expressions of the various collisionaI cross sections are presented. The results are applied to the experimtent, and several kinds of cross sections are obtained for the Na 2 -Ar system. Furthermore by assuming the Gaussian collision kernel, two parameters of the population kernel are derived for the Na 2 ( X Σ )-Ar collisions.

Journal of the Physical Society of Japan•Sep 1, 1983•2 citations

Photon echo and stimulated photon echo study of various collisional-relaxation channels

Н. Н. Рубцова, L. S. Vasilenko, Хворостов Евгений Борисович

Collisional relaxation in SF6 gas and its mixtures with He and Xe is studied by photon echo and stimulated photon echo methods from the standpoint of the possibility of identifying the contributions of different types of collisions. The nonexponential nature of the kinetic curve of the photon echo is clearly observed for pure SF6, it is weaker in the mixture SF6+Xe, and it is virtually completely absent for high degrees of dilution of SF6 with helium. These features can be explained on the basis of estimates, made from experimental data, of the critical delay between the exciting pulses (for which the nonexponential behavior should be most strongly manifested). In pure SF6 it is possible to distinguish the contribution of the inelastic channel (rotational relaxation) and the contribution of weak collisions. To distinguish successfully the relaxation channels in mixtures with buffer gases a heavier buffer gas and a much better time resolution must be used. It is shown that data obtained on the orientation and alignment relaxation rates by the stimulated photon echo method can serve as an upper limit for the rates of inelastic processes which cannot be measured by the photon echo method. The combined use of photon echo and stimulated photon echo methods made it possible to obtain data on the cross sections for elastic and inelastic scattering of the collisional pairs SF6–SF6, SF6–Xe, and SF6–He.

Journal of Experimental and Theoretical Physics•Jul 1, 1999•1 citation
Photon echo and reverse transient grating measurements of the loss of electronic coherence for molecular iodine are presented. Systematic measurements of the coherence decay rate were made as a function of buffer gas. From the dependence of decay rate on numerical density, we calculated experimental cross sections of decoherence. These values range from 135 Å2 for helium to 1170 Å2 for I2. We find Lennard-Jones parameters for the long-range interactions responsible for decoherence which can be modeled by dispersion forces.
Time-resolved coherent anti-Stokes Raman scattering is applied to prepare and interrogate vibrational coherences on the ground electronic surface of molecular iodine isolated in Ar matrices. The coherence decay time shows a linear dependence on vibrational quantum numbers for v=3–15. The temperature dependence of decoherence rates is negligible for v<7 in the experimental range T=18–32 K. For a v=13, 14 superposition, the temperature dependence indicates dephasing by a 66 cm−1 pseudo-local phonon, just outside the Debye edge of the solid. The accuracy of the data is limited due to two-photon induced dissociation of the molecule, a process which is characterized using polarized fields. The T→0 limit of dephasing is discussed.
Time-resolved, electronically resonant, coherent anti-Stokes Raman scattering is used to prepare and interrogate vibronic coherences of molecular iodine in matrix Ar. Coherences that involve evolution on the excited B(3Π0u) state, first- and third-order coherences, decay in less than one vibrational period (τ<300 fs). In contrast, as many as 200 vibrational periods of motion can be observed for Raman-prepared wave packets consisting of zero-phonon vibrational superpositions on the ground electronic state (second-order coherence). Packets consisting of v=4, 5 and v=3, 4, 5 on the X(1Σg) state decay with a half-life of 10±1 ps at 31 K, allowing a more accurate measure of vibrational level spacings and decoherence time than has been possible in frequency domain. The harmonic frequency of the molecule is reduced by 1.5 cm−1 (0.7%) in the matrix. The lack of recurrence in the excited electronic state ensures that the resonant anti-Stokes scattering arises only from the negative momentum component of the Raman packet. This momentum filter, which should be ubiquitous in condensed media, leads to a signal with deeper modulation than in the gas phase.
A great variety of coherent transient processes in atomic and molecular gases is investigated. The degeneracy with respect to magnetic sublevels, which is typical of working levels of atomic and molecular transitions in gases, leads to new phenomena. In particular, the non-Faraday rotation of the coherent-response polarization vector at the 0 ↔ 1 transition is investigated in the presence of the longitudinal magnetic field in the 174 Yb vapor for both photon echo and stimulated photon echo. A specific relaxation channel that involves the depolarizing collisions emerges in a gas due to the degeneracy of working levels. Such collisions are especially important for atoms and are also observed in molecules. The anisotropy of the depolarizing collisions leads to a new phenomenon of the collision photon echo, which is experimentally demonstrated for the 0 ↔ 1 transition in the 174 Yb mixtures with atomic buffers. The velocity-dependent relaxation rates are observed for various coherent phenomena in molecular gases. The coherent control of a few coherent transient processes is implemented.
Backward photon echo and its decay were observed in the X Σ - A Σ transition of Na 2 undergoing collisions with Ar buffer gas. By using the quantum mechanical transport equation, expressions of the various collisionaI cross sections are presented. The results are applied to the experimtent, and several kinds of cross sections are obtained for the Na 2 -Ar system. Furthermore by assuming the Gaussian collision kernel, two parameters of the population kernel are derived for the Na 2 ( X Σ )-Ar collisions.
Collisional relaxation in SF6 gas and its mixtures with He and Xe is studied by photon echo and stimulated photon echo methods from the standpoint of the possibility of identifying the contributions of different types of collisions. The nonexponential nature of the kinetic curve of the photon echo is clearly observed for pure SF6, it is weaker in the mixture SF6+Xe, and it is virtually completely absent for high degrees of dilution of SF6 with helium. These features can be explained on the basis of estimates, made from experimental data, of the critical delay between the exciting pulses (for which the nonexponential behavior should be most strongly manifested). In pure SF6 it is possible to distinguish the contribution of the inelastic channel (rotational relaxation) and the contribution of weak collisions. To distinguish successfully the relaxation channels in mixtures with buffer gases a heavier buffer gas and a much better time resolution must be used. It is shown that data obtained on the orientation and alignment relaxation rates by the stimulated photon echo method can serve as an upper limit for the rates of inelastic processes which cannot be measured by the photon echo method. The combined use of photon echo and stimulated photon echo methods made it possible to obtain data on the cross sections for elastic and inelastic scattering of the collisional pairs SF6–SF6, SF6–Xe, and SF6–He.