Values Of Electron Energy Research Articles

The effect of gas mixture on the electron kinetics in the electrical CO2 gas laser

Detailed numerical calculations of electron transport coefficients and vibrational excitation rates in a He:N2:CO2 gas laser discharge have been carried out over a range 1×10−16≤E/N≤5×10−16 V cm2 for several gas mixtures. Comparison of the results indicate that the vibrational excitation processes in the CO2 molecule scale with the average electron energy and are approximately invariant with respect to gas mixture. At a fixed value of electron energy, the dominant effect of gas mixture variation is to modify the vibrational excitation rate into the nitrogen. The effect of gas mixture variation on electron drift velocity is greatest in CO2–He mixtures, but is substantially reduced when a small fraction of N2 is added.

Optical Absorptions in Metal Sodium: The Temperature Dependence in the Liquid State

The temperature dependence of optical absorptions in liquid Na is calculated. The electron energy values are obtained to second order in perturbation theory which are then used to determine the electron density of states. The density of states plots show some structure similar to those noted in the solid state. The optical conductivity in the liquid state is found to increase with the temperature as in the solid state. The present calculation for the optical conductivity gives a rather sharp peak around ħ ω = 1.7 eV. These results are in better agreement with the existing experimental results

Theoretical optimization of EBS targets

The analysis of the external circuit response and internal behavior of an electron-bombarded semiconductor diode (EBS target) has been extended using static and dynamic computer simulation techniques. This work complements the previous simplest case analytical treatment of target operation and makes possible the accurate evaluation of high-level target response with any or all of the following effects: arbitrary input current waveform; arbitrary pair-creation profile corresponding to arbitrary values of incident electron energy and drift-region width; operation where both electrons and holes contribute significantly to the target current; electric-field-dependent carrier drift velocities; arbitrary profile of drift-region doping; and effects due to carrier diffusion and recombination. Operation of the computer programs is briefly described for the static and time-dependent cases. Output waveforms and time-varying internaI electric field profiles are shown for two representative cases that violate the assumptions of the simplest case analytical treatment. The first target design shows that 500 A of output current can be switched into a 0.5-Ω load with 0.5-ns risetime. The second target design illustrates the effects that occur when the beam-generated electron-hole pair creation extends completely across the drift region. The analysis of this target also shows that current pulses of 30 A can be switched with a 40-ps risetime into a 1.4-Ω load. A comparison with experimental results shows good agreement under static and dynamic conditions.

A study of the de-excitation of primary fission fragments from the neutron-induced fission of 235U

Two separate three-dimensional experiments have been performed in which the energies of coincident fragment pairs and γ-rays or internal conversion electrons, emitted within ≈ 1.6 nsec of the thermal-neutron-induced fission of 235U, were recorded event by event. The fragment kinetic energies were used for mass identification. The self-consistency of the values of electron energy, γ-ray energy and fragment charge, and its agreement with X-ray selection data, were used to identify the atomic numbers of the fragments. The analysis of the γ-ray and conversion electron spectra resulted in the assignment of many transitions to new isotopes as well as improvement in or confirmation of many assignments from the 252Cf spontaneous fission data. Limited information on the multipolarities of the transitions in even nuclei is presented. The relative yield of electrons per fragment indicates softness to deformation in the mass region 100–110. Data are presented supporting the assignment of a 193 keV transition as the 2 + → 0 + transition in 98Sr. An examination of the 2 + → 0 + level systematics of neighbouring even nuclei suggests a transition from vibrational to rotational behaviour in the light fragments between neutron numbers 58 and 60.

Elastic scattering of electrons by fission antineutrinos

The scattering cross-sections for the elastic-scattering reaction\(\bar \nu _e + e^ - \to \bar \nu _e + e^ - \) taking into account the energy spectrum of electron-antineutrinos from235U fission have been calculated according to the photon-neutrino weak-coupling theory for several values of minimum electron energy from 1 to 5.5 MeV. The results are then compared with those derived according to theV-A theory. It is found that the present experimental upper limit for the cross-section as reported by Reines and Gurr is about 200 times the cross-section predicted with the photon-neutrino coupling theory. Finally, the arguments put forward by Stothers for the astrophysical exclusion of the photon-neutrino coupling theory are discussed and shown to be invalid in view of various uncertainties entering into the calculation of stellar evolution.

Spectroscopic and structural studies of some oxocarbon condensation products: VI. The electronic structures of some hydroxyphenazines and quinones

Pariser-Parr-Pople molecular orbital calculations, including some configuration interaction, are reported for some hydroxyphenazines and related quinones. In general there is satisfactory agreement between the calculated charge density, bond order, electronic transition energy and oscillator strength values when compared with the available experimental data.

Spectroscopic and structural studies of some oxocarbon condensation products: V. The electronic structures of some cyclobuta[ b]quin-oxalines

The electronic spectra of twelve cyclobuta[ b]quinoxalines are reported and compared with electronic transition energy and oscillator strength values derived from Pariser-Parr-Pople molecular orbital calculations. The effects of non-planarity on the electronic structures of these molecules are considered.

V−AElastic Scattering of Electrons by Fission Antineutrinos

The energy spectrum of electron antineutrinos from $^{235}\mathrm{U}$ fission products in secular equilibrium has been recalculated. Assuming the validity of $V\ensuremath{-}A$ theory, cross sections for the elastic scattering reaction ${\overline{\ensuremath{\nu}}}_{e}+{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\overline{\ensuremath{\nu}}}_{e}+{e}^{\ensuremath{-}}$, integrated over recoil electron energy for this antineutrino spectrum, are given for several values of minimum electron energy from 1 to 5.5 MeV. Theoretical error bars, which reflect the uncertainties in the input data, are given for the antineutrino spectrum and the cross sections.

Double brems radiation in the scattering of electrons by electrons at energies up to 2�160 MeV

The double brems radiation emitted during the scattering of electrons by electrons was studied with intersecting electron beams of the V'EP-1 storage ring. Measurements were made for three values of electron energy: 2 x 43, 2 x 135 and 2 x 160 MeV. Two total-absorption counters with NaI(TI) crystals were used in the experiments. The resultant total cross section of the process and also the energy distribution of the 3,-quanta agrees with the results of V. N. Baler and V. M. GalitskiPs theory.

Solution of the Thomas-Fermi-Dirac Equation with a Modified Weizsäcker Correction

According to the result obtained in a previous paper (J. Phys. Soc. Japan 20 (1965) 1051), the Weizsäcker correction is introduced into the TFD theory with a constant weighting factor λ(=0.2) and this extended statistical equation is solved for the electron distribution of the inert gas atoms Ne, Ar, Kr and Xe. The values of the total energy calculated on this basis agree very well to the Hartree-Fock values. The diamagnetic susceptibilities, however, still have a poor coincidence although the present model gives definitely better results compared to the simple TF or TFD theory. One electron energy values or the occupied states in Kr atom are also calculated by the Bohr-Sommerfeld quantization condition.

DETERMINATION OF THE MEAN FREE PATH OF SLOW ELECTRONS BY THE MEASUREMENT OF BACK-DIFFUSION IN HELIUM AND ARGON

In the theoretical examination of back-diffusion Varney found a relationship between the extent of the back-diffusion of electrons starting from the cathode and the distance to the cathode. When adequate conditions are ensured the dependence of back-diffusion on distance permits the determination of the mean free path of the electrons. A test device has been developed to measure back-diffusion as a function of the distance to the cathode, for electrons that have an energy distribution corresponding to the specified pressure and the field intensity. From the dependence on distance, mean free paths for helium and argon gases in the range from X/p = 0.5 volt/cm. mm Hg to X/p = 5 volts/cm. mm Hg have been determined. The results are in fair accordance with the mean free paths computed by Barbiere from electron-energy distribution values. Variances have been found, however, with Townsend's and Bailey's data, particularly in the case of argon, where the free path of electrons depends greatly on velocity.

Electronic energy states of diatomic amorphous substance

Abstract By means of a Green's function method a general expression is deduced for the energy values of an electron moving in a dimensional model of an amorphous solid, consisting of atoms of two different kinds placed alternately in arbitrary positions, each represented by a Dirac's σ-function. The general expression for the electronic energies is expressed in terms of wavefunctions at four different atomic sites of both kinds. From the general expression, the equations of the electronic energy values for some special cases are deduced.

Bond length alternation in pentalene

According to lcao-mo calculations lower π-electron and total electron energy values result if the molecular symmetry group for pentalene is taken to be C2h instead of D2h . Though a considerable reduction in π-electron energy is obtained, the gain in total electron energy is much smaller. Nevertheless it may be stated that in the ground state the twofold axes C2 x and C2 y are not present.

Splitting of the Proton Form Factors and Diffraction in the Proton

Separate proton form factors were obtained from electron scattering studies by choosing a pair of experimentally measured cross sections at the same value for the square of the momentum transfer but at different values of electron energy and scattering angle. The proton form factors obtained were plotted against the square of the momentum transfer. The new F/sub 2/ indicated that the Pauli magnetic moment cloud is a spread-out distribution. The constancy of F, however, suggested that the Dirac electric/magnetic cloud has a small, perhaps point-like, core. (M.C.G.)

Born Cross Sections for Inelastic Scattering of Electrons by Hydrogen Atoms. I.3s,3p,3dStates

Born cross sections of all $n=3$ to $n=4$ transitions are calculated at ten incident electron energy values in the range 0.67-1400 ev, and those of strong optically allowed $n=3$ to $n=5$ transitions are calculated at five incident electron energy values in the range 1-10 000 ev. The cross sections obtained are much larger than for comparable transitions from the ground state, and the cross sections for transitions which are optically allowed and in which $n$ and $l$ change in the same sense are larger than those for other transitions. For all strong optically allowed transitions the Bethe (dipole) approximations to the Born cross sections are calculated and comparison shows that the Bethe formula gives a good fit to the Born approximation down to relatively low energies (\ensuremath{\approx}10 ev).

The electron energy distribution in helium

Smit's data for the energy distribution amongst electrons drifting through helium when the ratio of the electric field to gas pressure is small have been extended to higher values of electron energy by development of his formulas. Attention is called to the possible inaccuracy of some collision data on which the calculations are based.

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