Relativistic coulomb excitation

Coulomb excitation of both target and projectile in relativistic heavy ion collisions is evaluated including the lowest order correction for the deviation from a straight line trajectory. Explicit results for differential and total cross sections are given in the form of tables and figures.     

Relativistic coulomb scattering without regularization

Asymptotic forms of Green functions for relativistic Coulomb scattering are constructed and the infrared singularity structure is identified to all orders in the potential. Zwanziger's reduction formulas for scalar and $\text{spin}\text{-}\text{1}\text{2}$ particles are proven to be finite to all orders. The question of the definition of the S-operator and the related difficulties of the forward direction singularity are explicitly discussed and the unitarity is proven on the basis of the asymptotic solutions and second order calculations.     

Simulation of coulomb explosion of metals

Coulomb explosion of a metal exposed to an intense picosecond laser pulse is numerically simulated using a plasma layer as an example. It is shown that plasma electrons leave the plasma layer under the action of the ponderomotive force opposing the laser radiation field gradient, whereas plasma ions fly away in the field of the self-space charge.     

Relativistic coulomb excitation of neutron-rich 54,56,58Cr

The first excited 2⁺ states in neutron-rich ^54,56,58Cr were populated by relativistic Coulomb excitation and B (E2, 2 ₁ ⁺ → 0⁺) values were determined for ⁵⁶Cr and ⁵⁸Cr. The B(E2) values show a minimum for ⁵⁶Cr providing evidence for a subshell closure at N=32.     

Relativistic coulomb collisions and the virtual radiation spectrum

We evaluate the Coulomb-excitation cross sections in relativistic heavy-ion collisions by means of the plane-wave Born approximation. The final total cross section is shown to be equal to that obtained by a semiclassical method. As a byproduct the virtual photon spectrum for similar electromagnetic processes is derived. Comparison with other methods is performed.     

Relativistic coulomb collisions and the virtual radiation spectrum

We evaluate the Coulomb-excitation cross sections in relativistic heavy-ion collisions by means of the plane-wave Born approximation. The final total cross section is shown to be equal to that obtained by a semiclassical method. As a byproduct the virtual photon spectrum for similar electromagnetic processes is derived. Comparison with other methods is performed.     

A mean spherical model with coulomb interactions

We consider simple cubic lattice systems ind dimensions with a continuous real charge variableq(n) at each lattice siten. These variables are subject t'o a mean spherical constraint forcing _n q ²(n)=Q ², where is the number of lattice sites in andQ is an elementary charge. The energy of the charges comes from interactions with an electrostatic potential, which is the solution of a symmetric second-difference Poisson equation on the lattice. Two cases are considered, both of which allow the inclusion of the effects of a fixed, constant, external electric field. On the lattice ₁=[1,N]^d , a Neumann condition is imposed at the surface of the lattice. The lattice ₂=[1,N] [–M,M]^(d–1) is periodic in each direction ranging over [–M, M] and has a Dirichlet condition imposed at the other two surfaces. On ₂ a finite electric field may be applied, while on ₂ a finite potential difference may be applied across the lattice. The models are exactly solvable. We study the distribution functions on each system and show that they satisfy appropriate forms of the first two Stillinger-Lovett moment conditions. The two charge distribution functions show screening behavior at high temperature and extreme short range at an intermediate temperatureT ₀(d), and oscillate as they decay to zero forT<T ₀(d). Because of the continuous nature of the charge variables, there is no Kosterlitz-Thouless transition in two dimensions. In three dimensions the change in the decay behavior of the distribution functions atT<T ₀(d) is precursor to a phase transition to a charge ordered state.     

Hydrodynamic description of laser-induced coulomb explosion for small molecules

We have performed extensive numerical studies of Coulomb explosion of small molecules such as CO2 and N2O with the help of a hydrodynamic model, which allows one to deal with many-electron systems in intense laser fields. The predicted kinetic energy releases of the fragmentation channels are in good agreement with the measured energies, using realistic molecular and laser excitation condition parameters.     

Relativistic dynamics of spherical timelike shells

The dynamics of general relativistic timelike spherically symmetric thin shells of matter is considered, putting special emphasis on the physical interpretation of the models and, therefore, on the dependence of the dynamical behavior upon then the choice of the equation of state. From this point of view the general formalism is reviewed both in the Israel’s and in the canonical (Lagrangian and Hamiltonian) approach. Known exact solutions corresponding to closed equations of state are reviewed as well, and a new, wide class of nonlinear barotropic solutions is introduced and discussed in detail.     

On the feasibility of the coulomb explosion of a metal

The mechanism of the Coulomb explosion of a metal in an external pulsed electric field is discussed. In the case of a low-frequency field, when its frequency is lower than the frequency of electron collisions, it is impossible to reach the conditions of the Coulomb explosion of a metal if the field pulse duration is shorter than the time of electron energy relaxation upon elastic collisions, and the electron temperature is well above the Fermi energy and the work function. In the case of a high-frequency field, e.g., in a powerful pulse of ultraviolet laser radiation, the Coulomb explosion can occur if the field strength is well above the intraatomic field strength (i.e., when the laser power density is ≥10¹⁹ W/cm²).     

Relativistic dynamics of spherical counter-rotating dust bodies

Spherically symmetric dust clusters, of the type first proposed by Einstein, are generalized to nonstationaxy cases. Particular attention is paid to a massive spherical shell of particles orbiting a central body, using a method developed by Israel. Shells provide comparisons with Schwarzschild test particles, and offer as well a simplified approach to continuously distributed clusters.     

Relativistic spherical polytropes: An analytical approach

Using the technique of Padé (2, 2) approximant we present, in this paper, an approximate analytical solution to the field equations of general relativity for time-independent, spherically symmetric systems in which the pressureP and density are related by a polytropic equation of state:P = K ^1+1/n. The boundary values of coordinate radius ₁, for polytropic indicesn = 0, 1.0 (0.5) 3.0, are given in Table I. Table II contains the values of other physical parameters, (₁) (mass), (the density concentration), and 2GM/c²R (the ratio of gravitational radius to the coordinate radius) forn = 0 and 1.Work done at Azerbaijan State University, Baku, USSR (1977–79).     

First direct observation of coulomb explosion during the formation of exotic atoms

A Doppler broadening of x-ray transitions from pionic nitrogen and muonic oxygen, which is attributed to Coulomb explosion of the molecules, has been observed by using a crystal spectrometer. Large linewidths indicate fast ionization of the molecules and a charge of (3-4)e for the accelerated fragments.     

Relativistic and QED contributions to the coulomb three-body system in muon-catalyzed fusion

Energy shifts in the shallowest level of the muonic moleculedtμ are estimated by using an accurate wave function of the point-charge three-body system which gives ε ₁₁ ⁰ = ?660.3 meV. Contributions of nuclear finite size, vacuum polarization, relativistic effect and internuclear interaction are evaluated to be +10.4 meV, +17.2 meV, +0.9 meV and ～ +10^?4 meV, respectively. These corrections to ε ₁₁ ⁰ amount to 28.5 meV, which is significantly different from the corresponding value 20.6 meV of the Soviet group, with serious dependence on the dtμ, formation rate.     

Controlling the coulomb explosion of silver clusters by femtosecond dual-pulse laser excitation

Silver clusters grown in helium nanodroplets are excited by intense femtosecond laser pulses resulting in the formation of a hot electron plasma far from equilibrium. The ultrafast dynamics is studied by applying optically delayed dual pulses, which allows us to pursue and control the coupling of the laser field to the clusters on a femtosecond time scale. A distinct influence of the optical delay on the ionization efficiency gives strong evidence that a significant contribution of collective dipolar electron motion is present, which is verified by corresponding Vlasov dynamics simulations on a model system. The microscopic approach demonstrates the outstanding role of giant resonances in clusters also in intense laser fields.     

H2D库仑爆炸中的同位素效应与尾流效应

对H2D+通过碳膜后的产物H+和D+的获取与测量,研究了H2D+的同位素效应以及离子穿过固体的尾流效应.H2D+的化学结构得到测定.H2D+的非对称结构得到确认.测量结果与通过其它方式对H2D+的研究结果相一致.     

Experimental evidence of excited multicharged atomic fragments coming from laser-induced coulomb explosion of molecules

Direct experimental evidence is presented for the production of excited multicharged atomic fragments in the laser-induced Coulomb explosion of molecules. The comparison of the fluorescence signals of several atomic and molecular species shows that the excited fragments come from transient excited multicharged molecules. The atomic fluorescence spectra recorded with NH3, N2, and N2O, in the 50-120 nm wavelength range, show that the excitation increases noticeably from NH3 to N2O. This effect is interpreted in terms of the initial electronic configuration, which favors a stronger excitation when the electronic density is more delocalized on the molecular nuclear structure.     

Dynamics and control of shock shells in the coulomb explosion of very large deuterium clusters

The explosion dynamics of very large (approximately 10(6)-10(7) atoms) deuterium clusters irradiated by ultraintense laser pulses (I approximately 10(18) W/cm(2)) is analyzed self-consistently with one-to-one three-dimensional and two-dimensional fully relativistic particle-in-cell simulations. Small-scale shock shells in the expanding ion cloud are observed. A technique to induce the formation of large shock shells inside a single cluster, increasing the probability of intracluster nuclear reactions, is proposed and demonstrated.     

A mean spherical model with coulomb interactions. II. Correlations at a free surface

Studies of the mean spherical model with Coulomb interactions are continued, by considering a system on ad-dimensional lattice which is periodic ind–1 dimensions and has a free surface in the remaining dimension. It is shown explicitly that correlations along the free surface decay asy ^–d ind dimensions and show that the surface properties of this model are those expected for a charged system in its plasma phase.