In this paper we want to study (n,3n) reactions using an empirical formula derived on the basis of the statistical model considering reaction Q-value dependence. This formula was obtained by taking into account the exponential dependence on asymmetry parameter (N-Z)/A for neutron-induced reactions in Levkovskii\'s empirical formula. In addition, the present formula depends also on incident energy En, reaction Q-value and symmetry term (N-Z)2/A. Herein, a new analysis of experimental data of (n,3n) reactions in the energy region 22-27.5 MeV was carried out for quick estimation of cross sections of the heavy mass isotopes of odd Z-even N nuclides in the region of A = 151 to 209. We observed a good agreement of the experimental cross section data with the calculations performed using the present empirical formula.

The cross-section calculation systematics for nuclear reactions have great importance in describing the particle-induced excitation of nuclei. In this study, for 14-15 MeV of incident neutron energy, it has been suggested new empirical formulae to describe the (n, 2p) reactions cross sections. The new empirical formulae have been obtained for 29≤A≤159, 29≤A≤103 and 133≤A≤159 mass ranges which are dependent on s=(N-Z)/A asymmetry parameter. The asymmetry parameters have been obtained by modifying the original Levkovski formula. Then, EXFOR data has been studied by applying the least square fitting method and (n, 2p) reactions systematics has been revealed. The statistical dependence (R2) of these data was examined in the 29≤A≤159 total mass range. The calculated results from the obtained formulae have been compared with the literature data. The predictions of our formulae are in good agreement with the EXFOR data for 29≤A≤159 and 29≤A≤103 mass range.

Past strategies for retrieving cloud optical properties from remote sensing assumed significant limits for desired parameters such as semi-infinite optical thickness, single scattering albedo equaling unity (non-absorbing scattering), absence of spectral dependence of the optical thickness, etc., and only one optical parameter could be retrieved (either optical thickness or single scattering albedo). Here, we demonstrate a new method based on asymptotic theory for thick atmospheres, and the presence of a diffusion domain within the clouds that does not put restrictions and makes it possible to get two or even three optical parameters (optical thickness, single scattering albedo and phase function asymmetry parameter) for every wavelength independently. We applied this method to measurements of angular distribution of solar radiation above, inside and below clouds, obtained with NASA\'s Cloud Absorption Radiometer (CAR) over two cases of marine stratocumulus clouds; first case, offshore of Namibia and the second case, offshore of California. The observational and retrieval errors are accounted for by regularization, which allows stable and smooth solutions. Results show good potential for parameterization of the shortwave radiative properties (reflection, transmission, radiative divergence and heating rate) of water clouds.

Accurate theoretical calculation of photoelectron angular distributions for general molecules is becoming an important tool to image various chemical reactions in real time. We show in this article that not only photoionization total cross sections but also photoelectron angular distributions can be accurately calculated using complex Gauss-type orbital (cGTO) basis functions. Our method can be easily combined with existing quantum chemistry techniques including electron correlation effects, and applied to various molecules. The so-called two-potential formula is applied to represent the transition dipole moment from an initial bound state to a final continuum state in the molecular coordinate frame. The two required continuum functions, the zeroth-order final continuum state and the first-order wave function induced by the photon field, have been variationally obtained using the complex basis function method with a mixture of appropriate cGTOs and conventional real Gauss-type orbitals (GTOs) to represent the continuum orbitals as well as the remaining bound orbitals. The complex orbital exponents of the cGTOs are optimized by fitting to the outgoing Coulomb functions. The efficiency of the current method is demonstrated through the calculations of the asymmetry parameters and molecular-frame photoelectron angular distributions of H2+ and H2 . In the calculations of H2 , the static exchange and random phase approximations are employed, and the dependence of the results on the basis functions is discussed. © 2017 Wiley Periodicals, Inc.

The complex basis function (CBF) method applied to various atomic and molecular photoionization problems can be interpreted as an L2 method to solve the driven-type (inhomogeneous) Schrödinger equation, whose driven term being dipole operator times the initial state wave function. However, efficient basis functions for representing the solution have not fully been studied. Moreover, the relation between their solution and that of the ordinary Schrödinger equation has been unclear. For these reasons, most previous applications have been limited to total cross sections. To examine the applicability of the CBF method to differential cross sections and asymmetry parameters, we show that the complex valued solution to the driven-type Schrödinger equation can be variationally obtained by optimizing the complex trial functions for the frequency dependent polarizability. In the test calculations made for the hydrogen photoionization problem with five or six complex Slater-type orbitals (cSTOs), their complex valued expansion coefficients and the orbital exponents have been optimized with the analytic derivative method. Both the real and imaginary parts of the solution have been obtained accurately in a wide region covering typical molecular regions. Their phase shifts and asymmetry parameters are successfully obtained by extrapolating the CBF solution from the inner matching region to the asymptotic region using WKB method. The distribution of the optimized orbital exponents in the complex plane is explained based on the close connection between the CBF method and the driven-type equation method. The obtained information is essential to constructing the appropriate basis sets in future molecular applications. © 2017 Wiley Periodicals, Inc.

Asymmetry parameters of the electric field gradient tensor at (75) As nuclei were determined for chalcogenide glassy semiconductors (CGS) of the Ge-As-Se system by comparing the experimental and simulated (75) As nuclear quadrupole resonance nutation interferograms. The electric field gradient asymmetry in CGS was analyzed, and it is believed that a structural change in these glassy semiconductors takes place at r¯ =  2.425. Electron paramagnetic resonance spectra of the Ge-As-Se system were obtained for the first time. A comparison was made between the results of analysis of the Ge-As-Se system by nuclear quadrupole resonance and electron paramagnetic resonance methods, and this allowed us to make the supposition that a structural phase transition occurs at r¯ = 2.4 from two-dimensional to three-dimensional CGS structure.