Author: Chunlei Guo
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
Multielectron Effects of Diatomic Molecules in Strong Laser Fields
Author: Chunlei Guo
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
A Framework for Understanding Molecular Dynamics in Strong Laser Fields
Author: Saipriya V. Menon
Publisher:
ISBN:
Category :
Languages : en
Pages : 230
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 230
Book Description
Diatomic Molecules in Strong Ultrashort Pulse Laser Fields
Author: John Paul Nibarger
Publisher:
ISBN:
Category :
Languages : en
Pages : 276
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 276
Book Description
Ionization and Dissociation Dynamics of Molecules in Strong Laser Fields
Author: Wei Lai
Publisher:
ISBN:
Category :
Languages : en
Pages : 147
Book Description
"The fast advancement of ultrashort-pulsed high-intensity laser technology allows for generating an electric field equivalent to the Coulomb field inside an atom or a molecule (e.g., Ec=5.14x109 V/cm at the 1s orbit radius a0=0.0529 nm of the hydrogen atom, which corresponds to an intensity of 3.54x1016 W/cm2). Atoms and molecules exposed in such a field will easily be ionized, as the external field is strong enough to remove the electrons from the core. This is usually referred to "strong field". Strong fields provide a new tool for studying the interaction of atoms and molecules with light in the nonlinear nonperturbative regime. During the past three decades, significant progress has been made in the strong field science. Today, most phenomena involving atoms in strong fields have been relatively well understood by the single-active-electron (SAE) approximation. However, the interpretation of these responses in molecules has encountered great difficulties. Not like atoms that only undergo excitation and ionization, various dissociation channels accompanying excitation and ionization can occur in molecules during the laser pulse interaction, which imparts further complexity to the study of molecules in strong fields. Previous studies have shown that molecules can behave significantly different from rare gas atoms in phenomena as simple as single and double ionization. Molecular dissociation following ionization also presents challenges in strong fields compared to what we have learned in the weak-field regime. This dissertation focuses on experimental studies on ionization and dissociation of some commonly-seen small molecules in strong laser fields. Previous work of molecules in strong fields will be briefly reviewed, particularly on some open questions about multiple dissociation channels, nonsequential double ionization, enhanced ionization and molecular alignment. The identification of various molecular dissociation channels by recent experimental technical upgrades will be shown. The study of enhanced ionization in small molecules by time-resolved pump-probe experiments and varying-pulse duration experiments will be discussed, followed by an investigation of molecular alignment effect in sequential and nonsequential dynamics. At last, selective charge separation in charge asymmetric dissociation of heteronuclear diatomic molecules will be shown and conclusion and future work will be discussed."--Pages vii-viii.
Publisher:
ISBN:
Category :
Languages : en
Pages : 147
Book Description
"The fast advancement of ultrashort-pulsed high-intensity laser technology allows for generating an electric field equivalent to the Coulomb field inside an atom or a molecule (e.g., Ec=5.14x109 V/cm at the 1s orbit radius a0=0.0529 nm of the hydrogen atom, which corresponds to an intensity of 3.54x1016 W/cm2). Atoms and molecules exposed in such a field will easily be ionized, as the external field is strong enough to remove the electrons from the core. This is usually referred to "strong field". Strong fields provide a new tool for studying the interaction of atoms and molecules with light in the nonlinear nonperturbative regime. During the past three decades, significant progress has been made in the strong field science. Today, most phenomena involving atoms in strong fields have been relatively well understood by the single-active-electron (SAE) approximation. However, the interpretation of these responses in molecules has encountered great difficulties. Not like atoms that only undergo excitation and ionization, various dissociation channels accompanying excitation and ionization can occur in molecules during the laser pulse interaction, which imparts further complexity to the study of molecules in strong fields. Previous studies have shown that molecules can behave significantly different from rare gas atoms in phenomena as simple as single and double ionization. Molecular dissociation following ionization also presents challenges in strong fields compared to what we have learned in the weak-field regime. This dissertation focuses on experimental studies on ionization and dissociation of some commonly-seen small molecules in strong laser fields. Previous work of molecules in strong fields will be briefly reviewed, particularly on some open questions about multiple dissociation channels, nonsequential double ionization, enhanced ionization and molecular alignment. The identification of various molecular dissociation channels by recent experimental technical upgrades will be shown. The study of enhanced ionization in small molecules by time-resolved pump-probe experiments and varying-pulse duration experiments will be discussed, followed by an investigation of molecular alignment effect in sequential and nonsequential dynamics. At last, selective charge separation in charge asymmetric dissociation of heteronuclear diatomic molecules will be shown and conclusion and future work will be discussed."--Pages vii-viii.
Progress in Ultrafast Intense Laser Science I
Author: See Leang Chin
Publisher: Springer Science & Business Media
ISBN: 3540344225
Category : Science
Languages : en
Pages : 338
Book Description
This is the first of a series of books on Ultrafast Intense Laser Science, a newly emerging interdisciplinary research field that spans atomic and molecular physics, molecular science, and optical science. It covers intense VUV laser-cluster interaction, resonance and chaos-assisted tunneling, and the effects of the carrier-envelope phase on high-order harmonic generation.
Publisher: Springer Science & Business Media
ISBN: 3540344225
Category : Science
Languages : en
Pages : 338
Book Description
This is the first of a series of books on Ultrafast Intense Laser Science, a newly emerging interdisciplinary research field that spans atomic and molecular physics, molecular science, and optical science. It covers intense VUV laser-cluster interaction, resonance and chaos-assisted tunneling, and the effects of the carrier-envelope phase on high-order harmonic generation.
Dynamics of Diatomic Molecules in Intense Laser Fields
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
A realistic description of ionization in intense laser fields is implemented into the Non-Adiabatic Quantum Molecular Dynamics (NA-QMD) formalism. First, the error of a finite basis expansion is considered and a new measure is proposed for time-dependent calculations. This is used to investigate systematically the influence of the used basis set in calculations on the hydrogen atom in intense laser fields. Second, absorbing boundary conditions in basis expansion are introduced via an imaginary potential into the effective one-particle Hamiltonian. It is shown that the used form of the absorber potential is valid in many-electron time-dependent density functional theory calculations, i.e. that only ionized states are affected by the absorbing potential. The absorber is then tested on reference calculations that exist for H and aligned H+2 in intense laser fields. Excellent agreement is found. Additionally, an approximative treatment of the missing electron-nuclear correlations is proposed. It is found in calculations on H+2 that a qualitative improvement of the description of nuclear dynamics results. The extension of the NA-QMD formalism is then used to investigate the alignment behavior of diatomic molecules. Recent experiments on H+2 and H2 are reviewed and explained. It is found that dynamic alignment, i.e. the laser induced rotation of the molecule, plays a central role. The alignment behavior of H+2 and H2 and its intensity dependence is investigated after that. A drastic difference between H+2 and H2 is found in NA-QMD as well as model calculations. Then, the focus is on an astonishing new effect that has been found in N2 calculations. This effect which is called "rotational destabilization" is studied on the model system H+2. Yet, it might be observable only in heavy dimers and might have already been found in an experiment on I2.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
A realistic description of ionization in intense laser fields is implemented into the Non-Adiabatic Quantum Molecular Dynamics (NA-QMD) formalism. First, the error of a finite basis expansion is considered and a new measure is proposed for time-dependent calculations. This is used to investigate systematically the influence of the used basis set in calculations on the hydrogen atom in intense laser fields. Second, absorbing boundary conditions in basis expansion are introduced via an imaginary potential into the effective one-particle Hamiltonian. It is shown that the used form of the absorber potential is valid in many-electron time-dependent density functional theory calculations, i.e. that only ionized states are affected by the absorbing potential. The absorber is then tested on reference calculations that exist for H and aligned H+2 in intense laser fields. Excellent agreement is found. Additionally, an approximative treatment of the missing electron-nuclear correlations is proposed. It is found in calculations on H+2 that a qualitative improvement of the description of nuclear dynamics results. The extension of the NA-QMD formalism is then used to investigate the alignment behavior of diatomic molecules. Recent experiments on H+2 and H2 are reviewed and explained. It is found that dynamic alignment, i.e. the laser induced rotation of the molecule, plays a central role. The alignment behavior of H+2 and H2 and its intensity dependence is investigated after that. A drastic difference between H+2 and H2 is found in NA-QMD as well as model calculations. Then, the focus is on an astonishing new effect that has been found in N2 calculations. This effect which is called "rotational destabilization" is studied on the model system H+2. Yet, it might be observable only in heavy dimers and might have already been found in an experiment on I2.
Nuclear Dynamics and Ionization of Diatomic Molecules in Intense Laser Fields
Author: Maia Magrakvelidze
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
In this work we studied the dynamics of deuterium molecules in intense laser fields both experimentally and theoretically. For studying the dynamics of the molecule on a time scale that is less than the period of the laser field (2.7 fs for 800 nm), an advanced experimental technique: COLTRIMS (cold target recoil ion momentum spectroscopy) was used. COLTRIMS allows studying the nuclear dynamics without using attosecond laser pulses. This thesis consists of two main parts. In the first part we deduced the angular dependence of the ionization probability of the molecule without aligning the molecules, by measuring the relative angle between a deuteron resulting from field dissociation and an emitted electron using electron-ion coincidence measurements with circularly polarized light in COLTRIMS. We found out that for 50 fs pulses (1850 nm wavelength and 2 x10[superscript]14 W/cm[superscript]2 intensity), D[subscript]2 molecules are 1.15 times more likely to be ionized when the laser field is parallel to the molecular axis than when the laser field is perpendicular. This result agreed perfectly with the result from our ab initio theoretical model and also with predictions of the molecular Ammosov-Delone-Krainov (mo-ADK) theory. In the second part of this work we calculated the time evolution of an initial nuclear wave packet in D[subscript]2[superscript]+ generated by the rapid ionization of D[subscript]2 by an ultra short laser pulse. We Fourier transformed the nuclear probability density with respect to the delay between the pump and probe pulses and obtained two-dimensional internuclear-distance-dependent power spectra which serve as a tool for visualizing and analyzing the nuclear dynamics in D[subscript]2[superscript]+ in an external laser field. We attempt to model realistic laser pulses, therefore in addition to the main spike of the pulse we include the Gaussian pedestal. The optimal laser parameters for observing field-induced bond softening and bond hardening in D[subscript]2[superscript]+ can be achieved by varying the intensity, wavelength, and duration of the probe-pulse pedestal. Despite the implicit "continuum wave" (infinite pulse length) assumption the validity of the "Floquet picture" is tested for the interpretation of short-pulse laser-molecule interactions.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
In this work we studied the dynamics of deuterium molecules in intense laser fields both experimentally and theoretically. For studying the dynamics of the molecule on a time scale that is less than the period of the laser field (2.7 fs for 800 nm), an advanced experimental technique: COLTRIMS (cold target recoil ion momentum spectroscopy) was used. COLTRIMS allows studying the nuclear dynamics without using attosecond laser pulses. This thesis consists of two main parts. In the first part we deduced the angular dependence of the ionization probability of the molecule without aligning the molecules, by measuring the relative angle between a deuteron resulting from field dissociation and an emitted electron using electron-ion coincidence measurements with circularly polarized light in COLTRIMS. We found out that for 50 fs pulses (1850 nm wavelength and 2 x10[superscript]14 W/cm[superscript]2 intensity), D[subscript]2 molecules are 1.15 times more likely to be ionized when the laser field is parallel to the molecular axis than when the laser field is perpendicular. This result agreed perfectly with the result from our ab initio theoretical model and also with predictions of the molecular Ammosov-Delone-Krainov (mo-ADK) theory. In the second part of this work we calculated the time evolution of an initial nuclear wave packet in D[subscript]2[superscript]+ generated by the rapid ionization of D[subscript]2 by an ultra short laser pulse. We Fourier transformed the nuclear probability density with respect to the delay between the pump and probe pulses and obtained two-dimensional internuclear-distance-dependent power spectra which serve as a tool for visualizing and analyzing the nuclear dynamics in D[subscript]2[superscript]+ in an external laser field. We attempt to model realistic laser pulses, therefore in addition to the main spike of the pulse we include the Gaussian pedestal. The optimal laser parameters for observing field-induced bond softening and bond hardening in D[subscript]2[superscript]+ can be achieved by varying the intensity, wavelength, and duration of the probe-pulse pedestal. Despite the implicit "continuum wave" (infinite pulse length) assumption the validity of the "Floquet picture" is tested for the interpretation of short-pulse laser-molecule interactions.
Dynamics of Diatomic Molecules in Intense Laser Fields
Author: Mathias Uhlmann
Publisher:
ISBN:
Category :
Languages : en
Pages : 143
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 143
Book Description
Intense Laser Phenomena and Related Subjects
Author: M. Yu Ivanov
Publisher:
ISBN: 9789814539999
Category : SCIENCE
Languages : en
Pages : 587
Book Description
Publisher:
ISBN: 9789814539999
Category : SCIENCE
Languages : en
Pages : 587
Book Description
Atoms, Solids, and Plasmas in Super-Intense Laser Fields
Author: Dimitri Batani
Publisher: Springer Science & Business Media
ISBN: 9780306466151
Category : Science
Languages : en
Pages : 434
Book Description
Proceedings of the 30th Course of the International School of Quantum Electronics on Atoms, Solids and Plasmas in Super-Intense Laser Fields, held 8-14 July, in Erice, Sicily
Publisher: Springer Science & Business Media
ISBN: 9780306466151
Category : Science
Languages : en
Pages : 434
Book Description
Proceedings of the 30th Course of the International School of Quantum Electronics on Atoms, Solids and Plasmas in Super-Intense Laser Fields, held 8-14 July, in Erice, Sicily