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We introduce a non-Hermitian Schrödinger-type approximation of optical Bloch equations for two-level systems. This approximation provides a complete and accurate description of the coherence and decoherence dynamics in both weak and strong laser fields at the cost of losing accuracy in the description of populations. In this approach, it is sufficient to propagate the wave function of the quantum system instead of the density matrix, providing that relaxation and dephasing are taken into account via automatically adjusted time-dependent gain and decay rates. The developed formalism is applied to the problem of scattering and absorption of electromagnetic radiation by a thin ...

Contributors
Puthumpally-Joseph, Raiju, Sukharev, Maxim, Charron, Eric, et al.
Created Date
2016-04-20

Using non-linear dielectric techniques, we have measured the dynamics of 5-methyl-3-heptanol at a temperature at which the Kirkwood correlation factor g[subscript K] indicates the coexistence of ring- and chain-like hydrogen-bonded structures. Steady state permittivity spectra recorded in the presence of a high dc bias electric field (17 MV/m) reveal that both the amplitude and the time constant are increased by about 10% relative to the low field limit. This change is attributed to the field driven conversion from ring-like to the more polar chain-like structures, and a direct observation of its time dependence shows that the ring/chain structural transition occurs ...

Contributors
Young-Gonzales, Amanda, Richert, Ranko, College of Liberal Arts and Sciences, et al.
Created Date
2016-08-16

We define the dielectric constant (susceptibility) that should enter the Maxwell boundary value problem when applied to microscopic dielectric interfaces polarized by external fields. The dielectric constant (susceptibility) of the interface is defined by exact linear-response equations involving correlations of statistically fluctuating interface polarization and the Coulomb interaction energy of external charges with the dielectric. The theory is applied to the interface between water and spherical solutes of altering size studied by molecular dynamics (MD) simulations. The effective dielectric constant of interfacial water is found to be significantly lower than its bulk value, and it also depends on the solute ...

Contributors
Dinpajooh, Mohammadhasan, Matyushov, Dmitry, College of Liberal Arts and Sciences, et al.
Created Date
2016-07-06

Singly deuterated silylene has been detected and characterized in the gas-phase using high-resolution, two-dimensional, optical spectroscopy. Rotationally resolved lines in the 0[0 over 0][˜ over X][superscript 1]A′ → [˜ over A][superscript 1]A′′000X˜1A′→A˜1A″ band are assigned to both c-type perpendicular transition and additional parallel, axis-switching induced bands. The extracted rotational constants were combined with those for SiH[subscript 2] and SiD[subscript 2] to determine an improved equilibrium bond length, r[subscript SiH], and bond angle, θ, of 1.5137 ± 0.0003 Å and 92.04° ± 0.05°, and 1.4853 ± 0.0005 Å and 122.48° ± 0.08° for the [˜ over X][superscript 1]A′(0, 0, 0) and ...

Contributors
Kokkin, Damian, Ma, Tongmei, Steimle, Timothy, et al.
Created Date
2016-06-27

A model of low-temperature polar liquids is constructed that accounts for the configurational heat capacity, entropy, and the effect of a strong electric field on the glass transition. The model is based on the Padé-truncated perturbation expansions of the liquid state theory. Depending on parameters, it accommodates an ideal glass transition of vanishing configurational entropy and its avoidance, with a square-root divergent enumeration function at the point of its termination. A composite density-temperature parameter ρ[superscript γ]/T, often used to represent combined pressure and temperature data, follows from the model. The theory is in good agreement with the experimental data for ...

Contributors
Matyushov, Dmitry, College of Liberal Arts and Sciences, Department of Physics, et al.
Created Date
2016-07-20

Electron transfer between redox proteins participating in energy chains of biology is required to proceed with high energetic efficiency, minimizing losses of redox energy to heat. Within the standard models of electron transfer, this requirement, combined with the need for unidirectional (preferably activationless) transitions, is translated into the need to minimize the reorganization energy of electron transfer. This design program is, however, unrealistic for proteins whose active sites are typically positioned close to the polar and flexible protein-water interface to allow inter-protein electron tunneling. The high flexibility of the interfacial region makes both the hydration water and the surface protein ...

Contributors
Matyushov, Dmitry, College of Liberal Arts and Sciences, Department of Physics, et al.
Created Date
2013