نتایج جستجو برای: neutral hole
تعداد نتایج: 143690 فیلتر نتایج به سال:
We modeled all stable positive and negative charge states of oxygen vacancies originating from the neutral O3 Si=Si O3 defect in amorphous SiO2 (a-SiO2) using an embedded cluster method on a distribution of structural sites. For the first time, we predict the geometry, electronic structure and spectroscopic properties of doubly ionized and negatively charged oxygen vacancies in a-SiO2 and demon...
Using the standard tight binding model of 2D graphite with short range electron repulsion, we predict a gapless spin-1, neutral collective mode branch below the particle-hole continuum with energy vanishing linearly with momenta at the Gamma and K points in the Brillouin zone. This spin-1 mode has a wide energy dispersion, 0 to approximately 2 eV, and is not Landau damped. The "Dirac cone spect...
We study the nonlinear gravitational collapse of a charged massless scalarfield. We confirm the existence of oscillatory inverse power-law tails along future timelike infinity, future null infinity and along the future outer-horizon. The nonlinear dumping exponents are in excellent agreement with the analytically predicted ones. Our results prove the analytic conjecture according to which a cha...
Oxygen vacancies in SiO2 have long been regarded as bistable, forming a Si-Si dimer when neutral and a puckered configuration when positively charged. We report first-principles calculations of O vacancies in amorphous SiO2 supercells that unveil significantly more complex behavior. We find that the vast majority of O vacancies do not pucker after capture of a hole, but are shallow traps. The r...
Using a simple model of a two-dimensional rectangular quantum box we study the effects of size and anisotropy on the energy and photoluminescence spectra of neutral and charged quantum dots. The competition of symmetries and energy/length scales of the free exciton or trion and of the confining potential is analyzed. The numerical calculations consisted of the diagonalization of the few-electro...
We construct a new static solution to the 5D Einstein-Maxwell equations describing a static black hole surrounded by a non-rotating dipole black ring. The configuration is kept in equilibrium by an external magnetic field interacting with the dipole charge of the black ring. The properties of the black Saturn-like configuration are studied and the basic physical quantities are calculated. The s...
We report a surprisingly long spin relaxation time of electrons in Mn-doped p-GaAs. The spin relaxation time scales with the optical pumping and increases from 12 ns in the dark to 160 ns upon saturation. This behavior is associated with the difference in spin relaxation rates of electrons precessing in the fluctuating fields of ionized or neutral Mn acceptors, respectively. For the latter, the...
Metal clusters serve as model systems to study basic problems of electronic correlation. Vacuum ultraviolet light from the free-electron laser FLASH ionizes 5d electrons from mass-separated negatively charged clusters, thus transiently leading to core-ionized neutral systems. Shielding of the core hole affects the electron binding energy. From the strong deviation from expectations of the metal...
The structure of the Asn102 mutant of trypsin was determined in order to distinguish whether the reduced activity of the mutant at neutral pH results from an altered active site conformation or from an inability to stabilize a positive charge on the active site histidine. The active site structure of the Asn102 mutant of trypsin is identical to the native enzyme with respect to the specificity ...
The purpose of this paper is to show that as a matter of principle, it is not appropriate to consider Schwarzschild black holes in thermal equilibrium with radiation because, even spinless and neutral holes undergo fluctuations of charge and angular momentum. Therefore, there will be a spread of these quantities around their zeromean values. We calculate these spreads for a black hole in therma...
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