The Experts below are selected from a list of 39 Experts worldwide ranked by ideXlab platform
Thomas L Schmidt - One of the best experts on this subject based on the ideXlab platform.
-
transient dynamics of a molecular quantum dot with a Vibrational Degree of freedom
Physical Review B, 2009Co-Authors: Romanpascal Riwar, Thomas L SchmidtAbstract:We investigate the transient effects occurring in a molecular quantum dot described by an Anderson-Holstein Hamiltonian, which is instantly coupled to two fermionic leads biased by a finite voltage. In the limit of weak electron-phonon interaction, we use perturbation theory to determine the time dependence of the dot population and the average current. The limit of strong coupling is accessed by means of a self-consistent time-dependent mean-field approximation. These complementary approaches allow us to investigate the dynamics of the inelastic effects occurring when the applied bias voltage exceeds the phonon frequency and the emergence of bistability.
-
charge transfer statistics of a molecular quantum dot with a Vibrational Degree of freedom
Physical Review B, 2009Co-Authors: Thomas L Schmidt, A KomnikAbstract:We analyze the full counting statistics of a single-site quantum dot coupled to a local Holstein phonon for arbitrary transmission and weak electron-phonon coupling. We identify explicitly the contributions due to quasielastic and inelastic transport processes in the cumulant generating function and discuss their influence on the transport properties of the dot. We find that in the low-energy sector, i.e., for bias voltage and phonon frequency much smaller than the dot-electrode contact transparency, the inelastic term causes a sign change in the shot noise correction at certain universal values of the transmission. Furthermore, we show that when the correction to the current due to inelastic processes vanishes, all the odd order cumulants vanish as well.
Romanpascal Riwar - One of the best experts on this subject based on the ideXlab platform.
-
transient dynamics of a molecular quantum dot with a Vibrational Degree of freedom
Physical Review B, 2009Co-Authors: Romanpascal Riwar, Thomas L SchmidtAbstract:We investigate the transient effects occurring in a molecular quantum dot described by an Anderson-Holstein Hamiltonian, which is instantly coupled to two fermionic leads biased by a finite voltage. In the limit of weak electron-phonon interaction, we use perturbation theory to determine the time dependence of the dot population and the average current. The limit of strong coupling is accessed by means of a self-consistent time-dependent mean-field approximation. These complementary approaches allow us to investigate the dynamics of the inelastic effects occurring when the applied bias voltage exceeds the phonon frequency and the emergence of bistability.
A Komnik - One of the best experts on this subject based on the ideXlab platform.
-
charge transfer statistics of a molecular quantum dot with a Vibrational Degree of freedom
Physical Review B, 2009Co-Authors: Thomas L Schmidt, A KomnikAbstract:We analyze the full counting statistics of a single-site quantum dot coupled to a local Holstein phonon for arbitrary transmission and weak electron-phonon coupling. We identify explicitly the contributions due to quasielastic and inelastic transport processes in the cumulant generating function and discuss their influence on the transport properties of the dot. We find that in the low-energy sector, i.e., for bias voltage and phonon frequency much smaller than the dot-electrode contact transparency, the inelastic term causes a sign change in the shot noise correction at certain universal values of the transmission. Furthermore, we show that when the correction to the current due to inelastic processes vanishes, all the odd order cumulants vanish as well.
Hua Guo - One of the best experts on this subject based on the ideXlab platform.
-
time independent quantum theory on Vibrational inelastic scattering between atoms and open shell diatomic molecules applications to no ar and no h scattering
Journal of Chemical Physics, 2020Co-Authors: Junxiang Zuo, Hua GuoAbstract:A full-dimensional rigorous quantum mechanical treatment of non-reactive inelastic scattering of an open-shell diatom [e.g., NO(2Π)] with a structureless and spinless atom is presented within the time-independent close-coupling framework. The inclusion of the diatomic Vibrational Degree of freedom allows the investigation of transitions between different Vibrational manifolds, in addition to those between different rotational, spin–orbit, and Λ-doublet states. This method is applied to the scattering of Vibrationally excited NO(2Π) with Ar and H (with its spin ignored). The former has negligible Vibrational inelasticity, thanks to the weak interaction between the two collisional partners. This conclusion justifies the commonly used two-dimensional approximation in treating NO scattering with rare gas atoms. The latter, on the other hand, is shown to undergo significant Vibrational relaxation, even in the ultra-cold regime, owing to a chemically bonded (HNO) complex on the lowest-lying singlet potential energy surfaces.
Yoichiro Matsumoto - One of the best experts on this subject based on the ideXlab platform.
-
dynamic molecular collision dmc model for rarefied gas flow simulations by the dsmc method
Physics of Fluids, 1999Co-Authors: Takashi Tokumasu, Yoichiro MatsumotoAbstract:The Dynamic Molecular Collision (DMC) model is constructed for accurate and realistic simulations of rarefied gas flows of nonpolar diatomic molecules by the Direct Simulation Monte Carlo (DSMC) method. This model is applicable for moderate temperatures (up to a few hundred K for nitrogen), where most molecules are in the Vibrational ground state and the Vibrational Degree of freedom can be neglected. In this range, moreover, the rotational energy can be considered as a continuous one. The collisions of diatomic molecules are simulated many times by the Molecular Dynamics (MD) method at various initial conditions. The site to site potential is used as an intermolecular one. The collision cross section is developed from the database obtained by MD simulation and kinetic theory of viscosity coefficient of diatomic molecules. The probability density function of energy after collision is also developed using the database. In order to verify the DMC model, two flow fields are simulated. First, the DMC model is applied to the simulation of the translational and rotational energy distribution at the equilibrium condition and the results are compared with the Maxwell distribution. The results agree very well with each other. Second, the DMC model is applied to the simulation of the rotational relaxation through low and high Mach number normal shock wave. These results also agree very well with the experimental results of Robben and Talbot, although the upstream rotational temperature is a little lower.