Debye model

About: Debye model is a research topic. Over the lifetime, 7462 publications have been published within this topic receiving 133987 citations.

Efficient energy transfer in light-harvesting systems: Quantum-classical comparison, flux network, and robustness analysis

Abstract: Following the calculation of optimal energy transfer in thermal environment in our first paper [J. L. Wu, F. Liu, Y. Shen, J. S. Cao, and R. J. Silbey, New J. Phys. 12, 105012 (2010)], full quantum dynamics and leading-order "classical" hopping kinetics are compared in the seven-site Fenna-Matthews-Olson (FMO) protein complex. The difference between these two dynamic descriptions is due to higher-order quantum corrections. Two thermal bath models, classical white noise (the Haken-Strobl-Reineker (HSR) model) and quantum Debye model, are considered. In the seven-site FMO model, we observe that higher-order corrections lead to negligible changes in the trapping time or in energy transfer efficiency around the optimal and physiological conditions (2% in the HSR model and 0.1% in the quantum Debye model for the initial site at BChl 1). However, using the concept of integrated flux, we can identify significant differences in branching probabilities of the energy transfer network between hopping kinetics and quantum dynamics (26% in the HSR model and 32% in the quantum Debye model for the initial site at BChl 1). This observation indicates that the quantum coherence can significantly change the distribution of energy transfer pathways in the flux network with the efficiency nearly the same. The quantum-classical comparison of the average trapping time with the removal of the bottleneck site, BChl 4, demonstrates the robustness of the efficient energy transfer by the mechanism of multi-site quantum coherence. To reconcile with the latest eight-site FMO model which is also investigated in the third paper [J. Moix, J. L. Wu, P. F. Huo, D. F. Coker, and J. S. Cao, J. Phys. Chem. Lett. 2, 3045 (2011)], the quantum-classical comparison with the flux network analysis is summarized in Appendix C. The eight-site FMO model yields similar trapping time and network structure as the seven-site FMO model but leads to a more disperse distribution of energy transfer pathways.

Bound states of helium atom in dense plasmas

Abstract: We have obtained the bound 1s21S, 1s2s1,3S, and 1s2p1,3P states energies of helium atom in dense plasma environments in accurate variation calculations. A screened Coulomb potential to represent the Debye model is used for the interaction between the charged particles. A correlated wave function consisting of a generalized exponential expansion has been used to take care of the correlation effect. The 1s21S, 1s2s1,3S, and 1s2p1,3P states energies along with the ionization potential, the energy splitting between the 1s2s3S, and 1s2s1S states, transition energies between the ground state and low-excited states of He estimated for various Debye lengths, are reported. The results show high degree of accuracy even under strong plasma conditions. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006

Temperature Dependence of the Debye Temperatures of Aluminum, Lead, and Beta Brass by an X-Ray Method

Abstract: The temperature dependence of the Debye temperature of aluminum, lead, and beta brass was determined by measuring the integrated intensity of a high angle x‐ray diffraction peak from each of the materials as a function of temperature. This measured temperature dependence agrees well with the corresponding function obtained from elastic constant data, although it is determined by much higher lattice frequencies. In agreement with the elastic constant measurements, evidence is found for an explicit temperature dependence beyond that resulting from the simple dependence of Debye temperature on volume.

Mechanisms for thermal conduction in methane hydrate.

Abstract: Crystalline clathrate hydrates exhibit an unusual thermal transport with glasslike thermal conductivity close to the Debye temperature but a crystal-like temperature dependence at low temperature. Molecular dynamics calculations on structure I methane clathrate hydrate reproduced the qualitative trend in the thermal conductivity. Analysis of the heat flux and local energy correlation functions shows that both the crystal structure of the clathrate framework and guest-host interactions contribute to thermal transport processes. The lower thermal conductivity relative to ice Ih is due to differences in crystal structures. The glasslike temperature dependence is governed by the guests and the guest-host interactions.