A5010734348- Atomic and Subatomic Physics Research
- Spectroscopy and Laser Applications
- Spectroscopy and Quantum Chemical Studies
- Advanced Chemical Physics Studies
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum, superfluid, helium dynamics
- Laser-Matter Interactions and Applications
- Quantum optics and atomic interactions
- Mass Spectrometry Techniques and Applications
- Molecular spectroscopy and chirality
- Photonic and Optical Devices
- Nuclear Physics and Applications
- Advanced Fiber Laser Technologies
- Advanced NMR Techniques and Applications
- Advanced Frequency and Time Standards
- Laser-Plasma Interactions and Diagnostics
- Atomic and Molecular Physics
- High-pressure geophysics and materials
- Mechanical and Optical Resonators
- Quantum Mechanics and Non-Hermitian Physics
- Magnetic confinement fusion research
- Optical Polarization and Ellipsometry
- Laser-induced spectroscopy and plasma
- Atmospheric Ozone and Climate
- Nuclear reactor physics and engineering
Foundation for Research and Technology Hellas
2015-2024
University of Crete
2015-2024
FORTH Institute of Electronic Structure and Laser
2002-2024
Forschungszentrum Jülich
2018-2023
Heinrich Heine University Düsseldorf
2023
RWTH Aachen University
2023
Istituto Nazionale di Fisica Nucleare, Sezione di Ferrara
2018-2019
Petersburg Nuclear Physics Institute
2018-2019
Kurchatov Institute
2018-2019
Budker Institute of Nuclear Physics
2018-2019
In this article we present a new approach to the already popular methods of ion imaging and velocity mapping. The novelty is that speed angular distributions are measured directly from images without need inverse Abel transformation as in conventional approaches. This achieved by using delayed pulsed extraction ions following photodissociation positioning nascent products. Delayed causes sufficient spread cloud such time width packet at detector on order 500 ns. By narrow gate (<40...
The mechanism for the reaction of atomic chlorine with vibrationally excited methane is investigated by measurement correlated state and scattering distributions using method core extraction (see preceding paper). Laser photolysis molecular creates monoenergetic atoms (≳98% Cl 2P3/2) that react molecules prepared linearly polarized infrared laser excitation. resulting HCl product population are determined (2+1) resonance-enhanced multiphoton ionization (REMPI), differential cross section...
Comparison of state-to-state differential cross sections for methane in the ground vibrational state to with one quantum asymmetric stretch excitation probes effect C−H on reaction atomic chlorine methane. We previously reported and HCl product population distributions vibrationally excited reaction. Here we report analogous measurements state. Photolysis molecular produces atoms that react molecules at 0.16 eV collision energy. Calibrated resonance-enhanced multiphoton ionization (REMPI)...
We observed directional dynamics in the photodissociation of an oriented molecule. When a laser dissociated hexapole-oriented carbonyl sulfide molecules, three-dimensional recoil carbon monoxide fragments, which we measured with ion imaging, was strongly asymmetric. obtained microscopic view molecular bond breaking that revealed both sign and magnitude deflection angle fragment frame. This experimental approach can be applied to study control photoinitiated reactions fixed molecules or by...
Photolysis of a molecule typically yields open-shell photofragments having angular momenta. A procedure is described for the measurement photofragment momentum distribution in terms polarization parameters aq(k)(p) which are expressed molecular frame and may be related to transition dipole matrix elements. The index (p) indicates either parallel (∥), perpendicular (⊥), or mixed (∥,⊥) both character. This has advantage that it decouples distributions from laboratory frame, gives new insight...
We describe a method we call core extraction for measuring the speed distributions of products from photoinitiated bimolecular reactions purpose determining state-to-state differential cross sections. Core is demonstrated by determination section reaction Cl+CH4(υ3=1)→HCl(υ=1, J=1)+CH3. The measures three-dimensional projections velocity distribution using time-of-flight mass spectrometer equipped with mask to reject off-axis scattered products. This projection then converted via simple...
Isolated diatomic molecules of iodine monochloride (ICl) were photodissociated by a beam linearly polarized light, and the resulting ground-state Cl atom photofragments detected method that is sensitive to handedness (helicity) electronic angular momentum. It was found this helicity oscillates between “topspin” “backspin” as function wavelength dissociating light. The originates solely from (de Broglie) matter-wave interference multiple pathways excited states ICl. These measurements can be...
We have applied the experimental technique of core extraction [W. R. Simpson et al., J. Chem. Phys. 103, 7299 (1995)] combined with resonance-enhanced multiphoton ionization (REMPI) a polarized laser beam to probe angular-momentum alignment HCl product reaction Cl vibrationally excited CH4(ν3=1). The method permits us distinguish products scattered in different directions center-of-mass frame, and thus we are able determine rotational for various scattering angles individual HCl(v,J) quantum...
Abstract We propose a new approach based on an all-optical set-up for generating relativistic polarized electron beams via vortex Laguerre-Gaussian (LG) laser-driven wakefield acceleration. Using pre-polarized gas target, we find that the topology of resolves depolarization issue injected electrons. In full three-dimensional particle-in-cell simulations, incorporating spin dynamics Thomas-Bargmann Michel Telegdi equation, LG laser preserves polarization by more than 80% while assuring...
Abstract We present an alternative formulation of quantum mechanical angular momentum, based on spatial wavefunctions that depend the Euler angles φ,θ,χ, and have additional internal projection n. The are Wigner D-functions, D_(n m)^s (φ,θ,χ), for which body-fixed number n has unusual value n=|s|=√(s(s+1)=s, or n=0. show states D_(s (φ,θ,χ) elementary particles with spin s give a gyromagnetic ratio g=2 s>0, we identify these as angular-momentum known fundamental charged spin. All...
The PREFER (Polarization REsearch for Fusion Experiments and Reactors) collaboration was born to address the know–how in different fields techniques challenging bet on fusion energy production with polarized fuel. Efforts are focused a variety of tasks objectives, which under responsibility institutes. Starting from open questions reaction physics, such as study D+D spin–dependent cross–sections measurements nuclear polarization conservation laser–induced plasmas, there is still unexplored...
The production of spin-polarized hydrogen atoms from the photodissociation chloride with circularly polarized 193-nanometer light is inferred measurement complete angular momentum distributions ground state Cl(2P3/2)and excited Cl(2P1/2)cofragments by slice imaging. experimentally measured and ab initio predicted a q(k) (p)parameters, which describe single-surface multiple-surface-interference contributions to distributions, are in excellent agreement. For laser pulses longer than about 0.7...
Photolysis of Cl2 initiates the title reaction at a sharply defined collision energy 0.24±0.03 eV. Nascent product rotational state distributions for HCl (v=0) are determined using resonance enhanced multiphoton ionization (REMPI), center-of-mass scattering measured by core-extraction technique, and average internal C2H5 is deduced from dependence core-extracted signal on photolysis polarization. The has little excitation, but distribution nearly isotropic. Although seemingly contradictory,...
We have studied the complete Cl-atom molecular-frame photofragment angular momentum distributions from photodissociation of Cl2 and ICl in 320–560 nm region using time-of-flight mass spectroscopy with laser detection. The experimental signals were analyzed polarization-parameter formalism described preceding paper. These experiments study three distinct cases. first case is 470 dissociation through B 3Π0+u state accessed via a parallel transition, yielding photofragments polarizations by...
Velocity distributions for the Cl(2P3/2) and Cl(2P1/2) photofragments produced by photolysis of Cl2 in region between 310 470 nm are measured using photofragment velocity mapping. Our results indicate that at short wavelengths absorption spectrum is dominated 1u(1Πu) excited electronic state which produces two ground chlorine atoms. The 0u+(B 3Πu) a spin-orbit atom becomes significant 350 dominates beyond 400 nm. Analysis angular indicates aligned magnitude alignment quantitatively...
We present the theory and experimental details for chiral-cavity-ring-down polarimetry magnetometry, based on ring cavities supporting counterpropagating laser beams. The optical-rotation symmetry is broken by presence of both chiral Faraday birefringence, giving rise to signal reversals which allow rapid background subtractions. measurement specific rotation at 800 nm vapors α-pinene, 2-butanol, α-phellandrene, optical sucrose solutions in a flow cell, Verdet constant fused silica,...
We measure nuclear and electron spin-polarized H D densities of at least ${10}^{19}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}3}$ with $\ensuremath{\sim}10\text{ }\mathrm{ns}$ lifetimes, from the photodissociation HBr DI circularly polarized UV light pulses. This density is $\ensuremath{\sim}6$ orders magnitude higher than that produced by conventional continuous-production methods and, surprisingly, 100 times expected for this method. observe hyperfine quantum beating magnetization a...
The photoloc technique can permit the measurement of not only state-to-state differential cross section but also its complete product polarization dependence for all moments orientation and alignment with k⩽2. We have realized this possibility reaction Cl+C2D6→DCl(v′=0,J′=1)+C2D5 at a collision energy 0.25 eV, which we measured section, 1/σ(dσ00/dΩr), four polarization-dependent A1(1)stf, A0(2)stf, A1(2)stf, A2(2)stf, in stationary target frame (STF), are defined by...
Slice imaging is used to measure directly the alignment of Br(2P3/2) and Cl(2P3/2) photofragments from photodissociation Br2 Cl2, respectively, at 355 nm, using an intensity-normalization method that does not require wavelength scanning probe laser. In both cases C 1Π(1u) state optically excited. The Br are maximally aligned populate mJ=±1/2 only, whereas Cl mJ=±3/2 by 80% 20%, respectively. These results show dissociates adiabatically, nonadiabatic transitions occur A 3Π(1u) during Cl2 dissociation.
We propose the measurement of cavity-enhanced parity-nonconserving (PNC) optical rotation in several transitions metastable Xe and Hg, including (2P(3/2)(o))6s(2)[3/2](2)(o)→(2P(1/2)(o))6s(2)[1/2](1)(o) Hg 6s6p (3)P(2)(o)→6s6p (1)P(1)(o), with calculated amplitude ratios E(1)(PNC)/M1=11×10(-8) 10×10(-8), respectively. demonstrate use a high-finesse bow-tie cavity counterpropagating beams longitudinal magnetic field, which allows absolute chiral rotation, path length enhancement about 10(4),...