Coherent control of atomic inner-shell x-ray lasing via perturbed valence-shell transitions

2021 ◽  
Vol 104 (3) ◽  
Author(s):  
Jianpeng Liu ◽  
Yongqiang Li ◽  
Li Wang ◽  
Jing Zhao ◽  
Jianmin Yuan ◽  
...  
Keyword(s):  
Coherent Control ◽  
Valence Shell ◽  
X Ray

Oscillator strength study of the excitations of valence-shell of C2H2 by high-resolution inelastic x-ray scattering

2021 ◽  
Author(s):  
Qiang Sun ◽  
Ya-Wei Liu ◽  
Yuan-Chen Xu ◽  
Li-Han Wang ◽  
Tian-Jun Li ◽  
...  
Keyword(s):  
High Resolution ◽  
Theoretical Models ◽  
High Energy ◽  
Oscillator Strengths ◽  
Electron Collision ◽  
Valence Shell ◽  
X Ray ◽  
X Ray Scattering ◽  
Theoretical Results ◽  
Ray Scattering

Abstract The oscillator strengths of the valence-shell excitations of C2H2 are extremely important for testing theoretical models and studying interstellar gases. In this study, the high-resolution inelastic x-ray scattering (IXS) method is adopted to determine the generalized oscillator strengths (GOSs) of the valence-shell excitations of C2H2 at a photon energy of 10 keV. The GOSs are extrapolated to their zero limit to obtain the corresponding optical oscillator strengths (OOSs). Through taking a completely different experimental method of the IXS, the present results offer the high energy limit for electron collision to satisfy the first Born approximation (FBA) and cross-check the previous experimental and theoretical results independently. The comparisons indicate that an electron collision energy of 1500 eV is not enough for C2H2 to satisfy the FBA for the large squared momentum transfer, and the line saturation effect limits the accuracy of the OOSs measured by the photoabsorption method.

scholarly journals Генерация аттосекундного импульса на основе коллективного спонтанного излучения слоя трехуровневых атомов, возбуждаемых парой униполярных импульсов

2020 ◽  
Vol 128 (11) ◽  
pp. 1723
Author(s):  
Р.М. Архипов ◽  
М.В. Архипов ◽  
И. Бабушкин ◽  
А.В. Пахомов ◽  
Н.Н. Розанов
Keyword(s):  
Hydrogen Atom ◽  
Key Words ◽  
Spontaneous Emission ◽  
Coherent Control ◽  
Generation Mechanism ◽  
Resonant Medium ◽  
Atomic Polarization ◽  
Short Pulses ◽  
X Ray ◽  
Free Polarization

Recently, for the generation of extremely short pulses, a method was proposed for coherent control of the polarization of a medium, based on the excitation of atomic polarization oscillations and their subsequent arrest using a pair of ultra short pulses. The so-called stopped pulse of polarization of the medium, which appears in the interval between its excitation and de-excitation, can be a source of an extremely short radiation pulse. In this paper, the indicated possibility of generating an isolated attosecond ultraviolet pulse in a three-level resonant medium, the parameters of which correspond to a hydrogen atom excited by a pair of unipolar X-ray pulses, is considered theoretically. In this case, the generation mechanism is "antenna", that is, it is caused by the collective spontaneous emission of pre-phased atoms in the absence of a noticeable decay of their free polarization. Key words: collective spontaneous emission, coherent control of atomic polarization, attosecond pulses, unipolar pulses, X-ray pulses, hydrogen atom.

Amplification of Elliptically Polarized Sub-Femtosecond Pulses in Neon-Like X-Ray Laser Modulated By An IR Field

2021 ◽  
Author(s):  
I. R. KHAIRULIN ◽  
V. А. АNTONOV ◽  
М. YU. RYABIKIN ◽  
M. A. BERRILL ◽  
V. N. SHLYAPTSEV ◽  
...  
Keyword(s):  
Harmonic Generation ◽  
Coherent Control ◽  
Polarization State ◽  
High Harmonic ◽  
High Harmonic Generation ◽  
Femtosecond Pulses ◽  
X Ray ◽  
On Demand ◽  
Attosecond Pulses ◽  
Elliptically Polarized

Abstract Amplification of attosecond pulses produced via high harmonic generation is a formidable problem since none of the amplifiers can support the corresponding PHz bandwidth. Producing the well defined polarization state common for a set of harmonics required for formation of the circularly/elliptically polarized attosecond pulses (which are on demand for dynamical imaging and coherent control of the spin flip processes) is another big challenge. In this work we show how both problems can be tackled simultaneously on the basis of the same platform, namely, the plasma-based X-ray amplifier whose resonant transition frequency is modulated by an infrared field.

The crystal structure of tetraethylammonium Tris(O-ethylxanthato)tellurate(II): An example of five-coordinate pentagonal-planar geometry

1976 ◽  
Vol 29 (11) ◽  
pp. 2337 ◽  
Author(s):  
BF Hoskins ◽  
CD Pannan
Keyword(s):  
Crystal Structure ◽  
Least Squares Method ◽  
Three Dimensional ◽  
Planar Geometry ◽  
Maximum Deviation ◽  
Valence Shell ◽  
X Ray Diffraction ◽  
Electron Pairs ◽  
Fourier Methods ◽  
X Ray

The crystal structure of tetraethylammonium tris(O-ethylxanthato) tellurate(11), [Et4N] [Te(S2COEt)3], has been determined by single-crystal three-dimensional X-ray diffraction methods. Crystals are monoclinic of space group P21/c with four cation-anion pairs per unit cell which has the dimensions a 8.121(1), b 18.858(2), c 19.260(2) � and β 105.22(2)�. The structure was solved by the normal Fourier methods and was refined with anisotropic thermal parameters by a full-matrix least-squares method converging with R and Rw values of 0.061 and 0.082 for the 2404 independent statistically significant reflections collected by counter methods. The tris(ethylxanthato)tellurate(11) anion has a novel five-coordinate pentagonal-planar structure with only two of the xanthato ligands bidentate and with the Te-S bond distances having values in the range 2.503(4)-3.059(3)�. The TeS5 atoms are coplanar, the maximum deviation from the plane being 0.122 �. This, together with the intra-planar S...S distances of 3.340-3.661 �, indicates that the ligand atoms of the pentagonal plane are not over-crowded. The geometry of the anion configuration can be explained in terms of the VSEPR theory using a pentagonal-bipyramidal arrangement of the seven electron pairs in the valence shell of the tellurium.

scholarly journals Moving the Frontier of Quantum Control into the Soft X-Ray Spectrum

2011 ◽  
Vol 2011 ◽  
pp. 1-4 ◽  
Author(s):  
A. Aquila ◽  
M. Drescher ◽  
T. Laarmann ◽  
M. Barthelmeß ◽  
H. N. Chapman ◽  
...  
Keyword(s):  
Free Electron Laser ◽  
Quantum Dynamics ◽  
Pulse Shaping ◽  
Quantum Control ◽  
Coherent Control ◽  
Control Pulse ◽  
Pulse Shaper ◽  
Time Resolved ◽  
X Ray ◽  
Recent Developments

The femtosecond nature of X-ray free electron laser (FEL) pulses opens up exciting research possibilities in time-resolved studies including femtosecond photoemission and diffraction. The recent developments of seeding X-ray FELs extend their capabilities by creating stable, temporally coherent, and repeatable pulses. This in turn opens the possibility of spectral engineering soft X-ray pulses to use as a probe for the control of quantum dynamics. We propose a method for extending coherent control pulse-shaping techniques to the soft X-ray spectral range by using a reflective geometry 4f pulse shaper. This method is based on recent developments in asymmetrically cut multilayer optic technology and piezoelectric substrates.

scholarly journals Coherent control of long-range photoinduced electron transfer by stimulated X-ray Raman processes

2016 ◽  
Vol 113 (36) ◽  
pp. 10001-10006 ◽  
Author(s):  
Konstantin E. Dorfman ◽  
Yu Zhang ◽  
Shaul Mukamel
Keyword(s):  
Electron Transfer ◽  
Long Range ◽  
Photoinduced Electron Transfer ◽  
Coherent Control ◽  
X Ray ◽  
On Demand ◽  
Model Complex ◽  
Resonant Raman ◽  
Opening Up

We show that X-ray pulses resonant with selected core transitions can manipulate electron transfer (ET) in molecules with ultrafast and atomic selectivity. We present possible protocols for coherently controlling ET dynamics in donor–bridge–acceptor (DBA) systems by stimulated X-ray resonant Raman processes involving various transitions between the D, B, and A sites. Simulations presented for a Ru(II)–Co(III) model complex demonstrate how the shapes, phases and amplitudes of the X-ray pulses can be optimized to create charge on demand at selected atoms, by opening up otherwise blocked ET pathways.

Testing aspherical atom refinements on small-molecule data sets

1978 ◽  
Vol 34 (6) ◽  
pp. 909-921 ◽  
Author(s):  
N. K. Hansen ◽  
P. Coppens
Keyword(s):  
Least Squares ◽  
Small Molecule ◽  
Error Function ◽  
Ammonium Thiocyanate ◽  
Data Sets ◽  
Valence Shell ◽  
X Ray ◽  
Additional Information ◽  
Experimental Resolution ◽  
Weak Structure

X-ray data on silicon, tetracyanoethylene, p-nitropyridine N-oxide and ammonium thiocyanate are refined with a generalized aspherical-atom formalism as introduced by Stewart, but modified to have a spherical valence more similar to the unperturbed HF valence shell. Several types of radial dependences of the multipole functions are tested and criteria are developed for judging the adequacy of the aspherical-atom refinement. The aspherical-atom model leads to a significant decrease in the least-squares error function, a reduction of features in the residual map, and an improvement in thermal parameters when comparison is made with the neutron results or when the rigid-bond postulate proposed by Hirshfeld is applied. Positional parameters are often improved except in the case of terminal atoms for which discrepancies, attributed to correlation between dipole-population and positional parameters, are sometimes observed. Deformation maps based on the aspherical-atom least-squares parameters contain less noise than X -- N maps and benefit from inclusion of calculated values of weak structure amplitudes in the summation. In the cases studied, deformation maps including terms beyond the experimental resolution do not yield additional information.

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