arXiv subjects

T. Maruyama

Publications and source records attributed to T. Maruyama.

77 records · Page 5Linked to original sources

arXiv2001

Photovoltage Effects in Photoemission from Thin GaAs Layers

A set of thin GaAs p-type negative electron affinity (NEA) photocathodes have been used to measure the yield of photoemitted electrons at high intensity excitation. The active layer thickness is 100 nm and the p-type doping ranges from 5\times10^{18} cm^{-3} to 5\times10^{19} cm^{-3} for a set of four samples. The results show that the surface escape probability is a linear function of the NEA energy. The surface photovoltage effect on photoemission is found to diminish to zero at a doping level of 5\times10^{19} cm^{-3}. The experimental results are shown to be in good agreement with calculations using a charge limit model based on surface photovoltage kinetics that assume a constant electron energy relaxation rate in the band bending region.

cond-mat.mtrl-sci↗

arXiv2000

Constraint Molecular Dynamics approach to Fermionic systems

We propose a Constraint Molecular Dynamics model for Fermionic system. In this approach the equations of motion of wave packets for the nuclear many-body problem are solved by imposing that the one-body occupation probability $\bar{f}(r,p,t)$ can assume only values less or equal to 1. This condition reflects the Fermionic nature of the studied systems and it is implemented with a fast algorithm which allows also the study of the heaviest colliding system. The parameters of the model have been chosen to reproduce the average binding energy and radii of nuclei in the mass region $A=30\sim 208$. Some comparison to data is given.

nucl-th↗

arXiv2000

Critical Phenomena in Finite Systems

We discuss the dynamics of finite systems within molecular dynamics models. Signatures of a critical behavior are analyzed and compared to experimental data both in nucleus-nucleus and metallic cluster collisions. We suggest the possibility to explore the instability region via tunneling. In this way we can obtain fragments at very low temperatures and densities. We call these fragments quantum drops.

nucl-th↗

arXiv1994

Antisymmetrization of a Mean Field Calculation of the T-Matrix

The usual definition of the prior(post) interaction $V(V^\prime )$ between projectile and target (resp. ejectile and residual target) being contradictory with full antisymmetrization between nucleons, an explicit antisymmetrization projector ${\cal A}$ must be included in the definition of the transition operator, $ T\equiv V^\prime{\cal A}+V^\prime{\cal A}GV. $ We derive the suitably antisymmetrized mean field equations leading to a non perturbative estimate of $T$. The theory is illustrated by a calculation of forward $α$-$α$ scattering, making use of self consistent symmetries.

nucl-th↗

arXiv1993

Momentum distribution of fragments in heavy ion reactions: Dependence on the stochastic collision process

Momentum distribution of fragments produced in 12C+12C reaction at 28.7 MeV/nucleon is analyzed with antisymmetrized version of molecular dynamics (AMD). Calculations are made for several cases of stochastic collisions and the projectile fragmentation peak in momentum distribution is reproduced by the incorporation of many-body nature in stochastic collision process. Furthermore the value of the cross section is found to be reflected in the low momentum part of fragments such as alpha particles and 9Be.

nucl-th↗