scholarly journals Electronic stopping of protons in xenon plasmas due to free and bound electrons

2013 ◽  
Vol 31 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Manuel D. Barriga-Carrasco ◽  
David Casas
Keyword(s):  
Oscillator Strength ◽  
Close Agreement ◽  
Noble Gases ◽  
Previous Literature ◽  
Free Electrons ◽  
Hartree Fock ◽  
Plasma Target ◽  
Strength Functions ◽  
Bound Electrons

AbstractIn this work, proton stopping due to free and bound electrons in a plasma target is analyzed. The stopping of free electrons is calculated using the dielectric formalism, well described in previous literature. In the case of bound electrons, Hartree-Fock methods and oscillator strength functions are used. Differences between both stopping, due to free and bound electrons, are shown in noble gases. Then, enhanced plasma stopping can be easily estimated from target ionization. Finally, we compare our calculations with an experiment in xenon plasmas finding a close agreement.

scholarly journals Energy loss of protons and He2+ beams in plasmas

2014 ◽  
Vol 16 (6) ◽  
pp. 1085-1090
Keyword(s):  
Hydrogen Plasma ◽  
Argon Plasma ◽  
Alpha Particles ◽  
Free Electrons ◽  
Ionization Degree ◽  
Saha Equation ◽  
Hartree Fock ◽  
Plasma Target ◽  
Strength Functions ◽  
Bound Electrons

<div> <p>In this work, the stopping power due to free and bound electrons in a plasma target is analyzed for two different kinds of projectile, protons and alpha particles. The stopping of free electrons is calculated using the dielectric formalism, well described in previous literature. In the case of bound electrons, Hartree-Fock methods and oscillator strength functions are used. The ionization degree of the plasma target is calculated using the Saha equation. Differences between the two methods of calculations for bound electrons are shown in noble gases. The influence of ionization is also estimated for argon plasma. Finally, we compare our calculations with two experiments. In the first one the stopping is calculated for protons in polyethylene plasma, and the second one the stopping is obtained for alpha particles in hydrogen plasma. In both cases, a good agreement with the experimental data is found.</p> </div> <p>&nbsp;</p>

scholarly journals Multiply ionized carbon plasmas with index of refraction greater than one

2007 ◽  
Vol 25 (1) ◽  
pp. 47-51 ◽  
Author(s):  
J. FILEVICH ◽  
J. GRAVA ◽  
M. PURVIS ◽  
M.C. MARCONI ◽  
J.J. ROCCA ◽  
...  
Keyword(s):  
Laser Interferometry ◽  
General Assumption ◽  
Capillary Discharge ◽  
Index Of Refraction ◽  
Carbon Ions ◽  
Free Electrons ◽  
X Ray ◽  
Computer Calculations ◽  
Approximation Analysis ◽  
Bound Electrons

For decades the analysis of interferometry have relied on the approximation that the index of refraction in plasmas is due solely to the free electrons. This general assumption makes the index of refraction always less than one. However, recent soft x-ray laser interferometry experiments with Aluminum plasmas at wavelengths of 14.7 nm and 13.9 nm have shown fringes that bend the opposite direction than would be expected when using that approximation. Analysis of the data demonstrated that this effect is due to bound electrons that contribute significantly to the index of refraction of multiply ionized plasmas, and that this should be encountered in other plasmas at different wavelengths. Recent studies of Silver and Tin plasmas using a 46.9 nm probe beam generated by a Ne-like Ar capillary discharge soft-ray laser identified plasmas with an index of refraction greater than one, as was predicted by computer calculations. In this paper we present new interferometric results obtained with Carbon plasmas at 46.9 nm probe wavelength that clearly show plasma regions with an index of refraction greater than one. Computations suggest that in this case the phenomenon is due to the dominant contribution of bound electrons from doubly ionized carbon ions to the index of refraction. The results reaffirm that bound electrons can strongly influence the index of refraction of numerous plasmas over a broad range of soft x-ray wavelengths.

Luminescence from evaporated films of CdS

1969 ◽  
Vol 47 (23) ◽  
pp. 2591-2595 ◽  
Author(s):  
J. Conradi
Keyword(s):  
Surface Concentration ◽  
Peak Position ◽  
Luminescence Spectra ◽  
Free Electrons ◽  
Pulsed Electron Beam ◽  
Simultaneous Emission ◽  
Electron Beam Excitation ◽  
Bound Electrons ◽  
Concentration Of Electrons ◽  
Beam Excitation

Luminescence spectra from evaporated films of CdS are obtained under pulsed electron beam excitation. The transitions giving rise to the luminescence are identified as resulting from the recombination of bound electrons with bound holes and the simultaneous emission of n LO phonons (n = 0, 1, 2, … ), and the recombination of free electrons with bound holes. The addition of a 2000 Å thick coating of SiOx on top of the CdS is shown to produce a degenerate surface concentration of electrons which shifts the peak position of the free–bound transition to higher energies.

On the Ground State of H-

1981 ◽  
Vol 36 (7) ◽  
pp. 782
Author(s):  
Uday Vanu Das Gupta ◽  
Subal Chandra Saha ◽  
Sankar Sengupta
Keyword(s):  
Oscillator Strength ◽  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Expectation Values ◽  
Hartree Fock ◽  
Present Procedure

Abstract A simple and effective method is described to calculate the ground state energy of H~ starting with the Hartree Fock wavefunction. The expectation values of the opera­ tors 〈r1 • r2〉, 〈r1n + r2n〉 and 〈p1 • p2〉 can be estimated easily with the present procedure. Oscillator strength sums S(k) for k= -1,0, 1 are also evaluated.

scholarly journals Stopping power of a heterogeneous warm dense matter

2016 ◽  
Vol 34 (2) ◽  
pp. 306-314 ◽  
Author(s):  
D. Casas ◽  
A.A. Andreev ◽  
M. Schnürer ◽  
M.D. Barriga-Carrasco ◽  
R. Morales ◽  
...  
Keyword(s):  
Special Kind ◽  
Dense Matter ◽  
Stopping Power ◽  
Free Electrons ◽  
Warm Dense Matter ◽  
Excitation Energies ◽  
Plasma Density Profile ◽  
Individual Contributions ◽  
The Individual ◽  
Bound Electrons

AbstractThe stopping power of warm dense matter (WDM) is estimated by means of the individual contributions of free electrons and bound electrons existing in this special kind of matter, located between classical and degenerate plasmas. For free electrons, the dielectric formalism, well described in our studies, is used to estimate the free electron stopping power. For bound electrons, the mean excitation energy of ions is used. Excitation energies are obtained through atomic calculations of the whole atom or, shell by shell in order to estimate their stopping power. Influence of temperature and density is analyzed in case of an impinging projectile. This influence becomes important for low projectile velocities and is negligible for high ones. Using free and bound electron analysis, the stopping power of an extended WDM is inferred from a dynamical calculation of energy transferred from the projectile to the plasma, where the stopping range is calculated. Finally, this theoretical framework is used to study a typical plasma density profile of a WDM heated by lasers.

scholarly journals A mathematical model for DNA

2017 ◽  
Vol 14 (11) ◽  
pp. 1750152 ◽  
Author(s):  
Alireza Sepehri
Keyword(s):  
Mathematical Model ◽  
Radio Waves ◽  
Dna Molecules ◽  
Free Electrons ◽  
Men And Women ◽  
Dna Molecule ◽  
Electromagnetic Signals ◽  
M Theory ◽  
Bound Electrons ◽  
Damaged Dna

Recently, some authors have shown that a DNA molecule produces electromagnetic signals and communicates with other DNA molecules or other molecules. In fact, a DNA acts like a receiver or transmitter of radio waves. In this paper, we suggest a mathematical model for the DNA molecule and use of its communication to cure some diseases like cancer. In this model, first, by using concepts from string theory and M-theory, we calculate the energy of a DNA in terms of interactions between free electrons and bound electrons. We show that when a DNA is damaged, its energy changes and an extra current is produced. This extra current causes the electromagnetic signals of a damaged DNA molecule to be different when compared to the electromagnetic signals of a normal DNA molecule. The electromagnetic signals of a damaged DNA molecule induce an extra current in a normal DNA molecule and lead to its destruction. By sending crafted electromagnetic signals to normal DNA molecules and inducing an opposite current with respect to this extra current, we can prevent the destruction of normal DNA. Finally, we argue that the type of packing of DNA in chromosomes of men and women is different. This causes radiated waves from DNAs of men and women to have opposite signs and cancel the effect of each other in a pair. Using this property, we suggest another mechanism to cancel the effect of extra waves, which are produced by DNAs in cancer cells of a male or a female, by extra waves which are produced by DNAs in similar cells of a female or a male and prevent the progression of the disease.

The diamagnetism of quasi-bound conduction electrons

1953 ◽  
Vol 49 (2) ◽  
pp. 292-298 ◽  
Author(s):  
A. H. Wilson
Keyword(s):  
Magnetic Field ◽  
Partition Function ◽  
Power Series ◽  
Density Matrix ◽  
Complete Solution ◽  
Exact Expression ◽  
Free Electrons ◽  
Conduction Electrons ◽  
Image Position ◽  
Bound Electrons

The diamagnetism of the conduction electrons gives rise to some of the most difficult problems in the theory of metals, the complete solution of which has not yet been found. Formally, the problem is equivalent to determining the density matrixand the exact expression for ψ(r′, r, γ) for perfectly free electrons in a constant magnetic field H has recently been found by Sondheimer and Wilson(2). The extension of the theory to deal with quasi-bound electrons for all values of H seems to be out of the question, but an approximate partition function was given by Peierls (1), excluding terms of higher order than H2. In The theory of metals ((3), referred to as T.M.) I gave a more powerful and simpler method of dealing with the problem, based upon the properties of ψ(r′, r, γ), but since the solution was obtained as a power series in μ0Hγ, where it could at best determine only the normal diamagnetism.

The Maxwellian nature of free-electrons' gas spectrum of noble gases at low pressure

Vacuum ◽  
2014 ◽  
Vol 110 ◽  
pp. 19-23 ◽  
Author(s):  
Mališa Alimpijević ◽  
Koviljka Stanković ◽  
Milan Ignjatovic ◽  
Jovan Cvetić
Keyword(s):  
Noble Gases ◽  
Low Pressure ◽  
Free Electrons

scholarly journals Opacity and conductivity measurements in noble gases at conditions of planetary and stellar interiors

2015 ◽  
Vol 112 (26) ◽  
pp. 7925-7930 ◽  
Author(s):  
R. Stewart McWilliams ◽  
D. Allen Dalton ◽  
Zuzana Konôpková ◽  
Mohammad F. Mahmood ◽  
Alexander F. Goncharov
Keyword(s):  
High Pressures ◽  
Noble Gases ◽  
Structural Evolution ◽  
Wide Band ◽  
Amorphous Semiconductor ◽  
Stellar Atmospheres ◽  
Metallic Hydrogen ◽  
Free Electrons ◽  
White Dwarf Stars ◽  
Different Color

The noble gases are elements of broad importance across science and technology and are primary constituents of planetary and stellar atmospheres, where they segregate into droplets or layers that affect the thermal, chemical, and structural evolution of their host body. We have measured the optical properties of noble gases at relevant high pressures and temperatures in the laser-heated diamond anvil cell, observing insulator-to-conductor transformations in dense helium, neon, argon, and xenon at 4,000–15,000 K and pressures of 15–52 GPa. The thermal activation and frequency dependence of conduction reveal an optical character dominated by electrons of low mobility, as in an amorphous semiconductor or poor metal, rather than free electrons as is often assumed for such wide band gap insulators at high temperatures. White dwarf stars having helium outer atmospheres cool slower and may have different color than if atmospheric opacity were controlled by free electrons. Helium rain in Jupiter and Saturn becomes conducting at conditions well correlated with its increased solubility in metallic hydrogen, whereas a deep layer of insulating neon may inhibit core erosion in Saturn.

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