Cluster size effect on electron-induced luminescence

As a result of combined measurements of radiation intensity, electronically excited particles density and the density of mass-separated ions formed by a collision of electrons with CO₂, N₂O, H₂O molecules and clusters in intersecting beams it has been found that the process of ejection of electronically excited particles from clusters forms a main contribution to electron-induced luminescence in a mass-spectrum of molecular, fragmented and microcluster ions. The value of this contribution depends on the cluster sizeN. The enhancement of electron-induced luminescence by small clusters (N ? 15) has been found.     

Equidistant spectra of anharmonic oscillators

Some representative potentials of the anharmonic-oscillator type are constructed. Some corresponding spectra-shift operators are also constructed. These operators are a natural generalization of Fok creation and annihilation operators. The Schrodinger problem for these potentials leads to an equidistant energy spectrum for all excited states, which are separated from the ground state by an energy gap. The general properties of the dynamic system generated by spectral-shift operators of third degree are analyzed. Several examples of such anharmonic oscillators are discussed. The relationship between the eigenvectors of the Schrodinger problem and a certain type of nonclassical orthogonal polynomials is established.     

Local heating of a medium in the nanovicinity of the <Superscript>57</Superscript>Co nucleus that underwent radioactive decay to <Superscript>57</Superscript>Fe

Process of formation of the Auger blob (nanosized cloud of two or three hundred of ion–electron pairs) around a ⁵⁷Co radioactive atom after E-capture followed by the emission of a cascade of Auger electrons by the daughter atom ⁵⁷Fe has been considered. The effect of local temperature elevation in the Auger blob caused by energy emission during ionization slowing down of Auger electrons and the secondary electrons generated by them is discussed. Some consequences of this effect have been noted.     

Brown coal gasification in combustion in supercritical water

The yield and composition of conversion products are investigated in a layout that provides countersupply of reagents (brown coal, supercritical water (SCW), and O₂) into a vertical tubular reactor and drain of reactants into replaceable collectors under isobaric conditions (30 MPa). The coal (gross formula CH_0.96N_0.01S_0.002O_0.31) incorporated into coal-water slurry (CWS) stabilized by starch addition (1 wt.%), was supplied through the top end of the reactor, while SCW and SCW/O₂ fluids were supplied through the bottom end. Based on the results of elemental analysis of liquid products and solid residue of conversion, and mass spectrometric analysis of volatile products, we obtained gross reactions of brown coal conversion in SCW and SCW/O₂ fluids. It was found that addition of O₂ to SCW leads to autothermal conversion conditions and an increase in the contribution from heterogeneous reactions between carbon and water, which provides additional yield of H₂ and CH₄.     

Surface induced ionization of neutral water clusters

The paper presents the results of study of a new phenomenon — the formation of cluster ions of both signs in the scattering of neutral water clusters by solid surfaces and the appearance of a current to the target. The experiments were carried out by the nozzle molecular beam technique. The probabilities of the charge removal from the surface were measured in dependence on incident angle, cluster size, and target material. The model of the process has been proposed which incorporates 1) formation of an ion pair during ion dissociation of a vibrationally excited molecule in a water cluster colliding with the surface; 2) asymmetric neutralization of an ion pair by surface; 3) inertial removal of a cluster ion from the surface. However the measured angular and energy distribution of emitted charged particles testify to more complex mechanisms of ionization and scattering because the spatial pattern of ion emission is of rainbow character and in some cases the direction of inertial removal (along the tangential component of initial velocity) does not dominate.     

Ionization of water clusters by collision with surface

New results of the investigations of the phenomenon of the ion formation and separation at the neutral water cluster scattering by solid surface are reported. First, molecular dynamics simulation has shown the possibility of polar dissociation of water molecules in (H ₂ O)_n cluster with n = 34 and 64 during their impact with a rigid surface. Second, the current of ions rebound from target and the current to the target at scattering of (H2O)_n clusters (up to n = 50000) by various targets are measured. Third, we have measured the water-cluster-induced electrification of the electric field mill sensor, which has been used for the rocket measurement of mesospheric electric field structure in the vicinity of noctilucent clouds (NLC). A comparison between these and rocket measurements shows that the fluctuations of the field mill signal detected when a rocket was passing the NLC layer is a result of the impact of NLC particles on the field mill electrodes.