Principle Of Detailed Balance Research Articles

Note on electron energy can oscillate near a crystal dislocation

Recently Li et al. proposed an exactly-solvable one-dimensional quantum field theory of a dislocation for both edge as well as screw dislocations in an isotropic medium and, via the electron self-energy calculation, Li et al. claimed they can investigate directly the electron-dislocation relaxation time which is reducible to classical results obtained in [T. Ninomiya, J. Phys. Soc. Japan 25, 830 (1968)]. As the qualitative comparison is rather good thus Li et al. claimed the classical fluttering model prior to quantization has already obtained excellent agreement with experiments. However, as the present authors here point out, Ninomiya's approach and results are of doubt (violation of the principle of detailed balance; cf. V.I. Alshits and Yu. M. Sandler, Phys. Stat. Solidi (b) 64, K45 (1974) which performed the corrections: Doppler frequency shift effect included). In fact Ninomiya published a more complete paper latter on: Scr. Metal. 18, 669 (1984) which confirmed the critical remarks by Alshits and Sandier but Li et al. didn't notice or cite it. With above evidences Li et al. should seek quantitative. agreement with realistic materials so that the valid comparison with previous corrected theories considering the classical fluttering mechanism of dislocations can be confirmed. • Li et al.‘s dynamic fluttering dislocation scattering process was reexamined. • Li et al.‘s treatment of dislocation-phonon interaction was of doubt. • We illustrate Doppler frequency shift effect and violation of the principle of detailed balance.

Nonequilibrium Dissociation and Recombination Models for Hypersonic Flows

A recombination reaction model for high-temperature chemical kinetics is analytically derived from ab initio simulation data. When atoms recombine, the kinetic rate model shows that product molecules favor high vibrational energy states. In this manner, recombination repopulates high vibrational energy states depleted by dissociation, in a high-temperature reacting gas. Coupling of internal energy relaxation, dissociation, and recombination results in depleted or overpopulated (relative to a corresponding Boltzmann distribution) vibrational energy distributions. Through a simple model, we show that non-Boltzmann behavior, in other words, depletion or overpopulation of high-energy states, is not only linked to thermal nonequilibrium but also chemical nonequilibrium. The mathematical derivation also indicates that the conventional approach for modeling recombination rates, where shock-tube dissociation rate measurements are combined with the principle of detailed balance, is incorrect. The complete analytical dissociation/recombination model embeds all relevant kinetic processes, including specific terms for translation/rotation/vibration/chemistry coupling, anharmonic and quasi-bound effects, and non-Boltzmann depletion and overpopulation effects. The model is a multitemperature model that can be used within computational fluid dynamics simulations with no appreciable increase in computational expense. Finally, because the model is analytical, containing separate terms for various physical effects, further model simplification could be performed depending on the flow conditions of interest.

Mapping partial wave dynamics in scattering resonances by rotational de-excitation collisions.

One of the most important parameters in a collision is the 'miss distance' or impact parameter, which in quantum mechanics is described by quantized partial waves. Usually, the collision outcome is the result of unavoidable averaging over many partial waves. Here we present a study of low-energy NO-He collisions that enables us to probe how individual partial waves evolve during the collision. By tuning the collision energies to scattering resonances between 0.4 and 6 cm-1, the initial conditions are characterized by a limited set of partial waves. By preparing NO in a rotationally excited state before the collision and by studying rotational de-excitation collisions, we were able to add one quantum of angular momentum to the system and trace how it evolves. Distinct fingerprints in the differential cross-sections yield a comprehensive picture of the partial wave dynamics during the scattering process. Exploiting the principle of detailed balance, we show that rotational de-excitation collisions probe time-reversed excitation processes with superior energy and angular resolution.

Trajectory-based Simulation of Far-infrared Collision-induced Absorption Profiles of CH4–N2 for Modeling Titan’s Atmosphere

Abstract We report the results of the trajectory-based simulation of far-infrared collision-induced absorption (CIA) due to CH4–N2 pairs at temperatures between 70 and 400 K. Our analysis utilizes recently calculated high-level potential energy and induced dipole surfaces. Treating collision partners as rigid rotors, the time evolution of interaction-induced dipole is accumulated over a vast ensemble of classical trajectories and subsequently transformed into a CIA spectrum via Fourier transform. In our calculations, both bound and unbound states are properly accounted for, and the rigorous theory of lower-order spectral moments is addressed to check the accuracy of simulated profiles. Classically derived trajectory-based profiles are subject to two approximate desymmetrization procedures so that resulting profiles conform to the quantum principle of detailed balance. The simulated profiles are compared to laboratory measurements and employed for modeling Titan’s spectra in the 50–500 cm−1 range. Based on the desymmetrized simulated profiles, a new semiempirical model for CH4–N2 CIA is proposed for modeling Titan’s infrared spectra. Synthetic spectra derived using this model yield an excellent agreement with the data recorded by the Composite Infrared Spectrometer aboard the Cassini spacecraft at low and high emission angles.

Quasiequilibrium multistate cellular automata.

In our effort to tackle the problem of letting nontrivial interactions, thermodynamic equilibrium, and full synchronicity coexist, and in the hope of reviving interest in cellular automata as promising tools for the quantitative, large-scale investigation of multiparticle systems, we built a fully synchronous cellular automaton rule for the simulation of occupancy-based lattice systems with multistate cells and neighboring interactions. The core of this rule, which constitutes an actual synchronous sampling scheme, is a negotiation stage; it produces cell occupancy distributions in very good agreement with their sequential Monte Carlo counterparts, and it satisfies a cellwise detailed balance principle thanks to the use of "mixed" intermediate states that allow for the computation of locally averaged acceptance probabilities. We took a square lattice (but the rule itself is not bound by dimensionality) as a basis for comparison with sequential Monte Carlo for showing that this synchronous rule leads to quasiequilibrium; the fulfillment of cellwise detailed balance is shown through results obtained for a small one-dimensional system, where the transition matrix could be computed exactly.

Comment on Coleman-DeLuccia instantons

We complete an old argument that causal diamonds in the crunching region of the Lorentzian continuation of a Coleman-Deluccia instanton for transitions out of de Sitter space have finite area, and provide quantum models consistent with the principle of detailed balance, which can mimic the instanton transition probabilities for the cases where this diamond is larger or smaller than the causal patch of de Sitter space. We review arguments that potentials which do not have a positive energy theorem when the lowest de Sitter minimum is shifted to zero, may not correspond to real models of quantum gravity.

Misconceptions about the chemistry of aqueous chlorine atoms and HClOH˙(aq), and a revised mechanism for the photochemical peroxydisulfate/chloride reaction.

It is widely considered that aqueous chlorine atoms (Cl˙) convert to the species HClOH˙ with a half life of about 3 μs and that this species plays an important role in the chemistry of aqueous chlorine atoms. Here it is shown that there is no firm evidence for the existence of HClOH˙ as a species distinct from Cl˙, that the chemistry attributed to HClOH˙ can be accounted for by other well-established species, and that almost all published mechanisms that include reactions of HClOH˙ violate the principle of detailed balancing. More than 100 publications are identified that violate the principle of detailed balancing with HClOH˙ reactions. Proposals for the participation of HClOH˙ in reaction mechanisms originated in studies of the photochemical peroxydisulfate/chloride reaction; here we provide a revised mechanism that omits HClOH˙, complies with the principle of detailed balancing, and has a minimal number of reaction steps.

The principle of detailed balancing, the iron-catalyzed disproportionation of hydrogen peroxide, and the Fenton reaction

Over 200 publications report mechanisms that violate the principle of detailed balancing; a 10-step core mechanism is proposed that avoids these problems.

Equilibrium Spin Distribution From Detailed Balance

As the core ingredient for spin polarization, the equilibrium spin distribution function that eliminates the collision terms is derived from the detailed balance principle. The kinetic theory for interacting fermionic systems is applied to the Nambu–Jona-Lasinio model at quark level. Under the semi-classical expansion with respect to hbar , the kinetic equations for the vector and axial-vector distribution functions are obtained with collision terms. For an initially unpolarized system, spin polarization can be generated at the first order of hbar from the coupling between the vector and axial-vector charges. Different from the classical transport theory, the collision terms in a quantum theory vanish only in global equilibrium with Killing condition.

Over 15% efficient wide-band-gap Cu(In,Ga)S2 solar cell: Suppressing bulk and interface recombination through composition engineering

Over 15% efficient wide-band-gap Cu(In,Ga)S2 solar cell: Suppressing bulk and interface recombination through composition engineering

Influence of static disorder of charge transfer state on voltage loss in organic photovoltaics

Spectroscopic measurements of charge transfer (CT) states provide valuable insight into the voltage losses in organic photovoltaics (OPVs). Correct interpretation of CT-state spectra depends on knowledge of the underlying broadening mechanisms, and the relative importance of molecular vibrational broadening and variations in the CT-state energy (static disorder). Here, we present a physical model, that obeys the principle of detailed balance between photon absorption and emission, of the impact of CT-state static disorder on voltage losses in OPVs. We demonstrate that neglect of CT-state disorder in the analysis of spectra may lead to incorrect estimation of voltage losses in OPV devices. We show, using measurements of polymer:non-fullerene blends of different composition, how our model can be used to infer variations in CT-state energy distribution that result from variations in film microstructure. This work highlights the potential impact of static disorder on the characteristics of disordered organic blend devices.

Semiclassical Modified Redfield and Generalized Förster Theories of Exciton Relaxation/Transfer in Light-Harvesting Complexes: The Quest for the Principle of Detailed Balance

A conceptual problem of transfer theories that use a semiclassical description of the electron-vibrational coupling is the neglect of the correlation between momenta and coordinates of nuclei. In the Redfield theory of exciton relaxation, this neglect leads to a violation of the principle of detailed balance; equal “uphill” and “downhill” transfer rate constants are obtained. Here, we investigate how this result depends on nuclear reorganization effects, neglected in Redfield but taken into account in the modified Redfield theory. These reorganization effects, resulting from a partial localization of excited states, are found to promote a preferential “downhill” relaxation of excitation energy. However, for realistic spectral densities of light-harvesting antennae in photosynthesis, the reorganization effects are too small to compensate for the missing coordinate–momentum uncertainty. For weaker excitonic couplings as they occur between domains of strongly coupled pigments, we find the principle of detailed balance to be fulfilled in a semiclassical variant of the generalized Förster theory. A qualitatively correct description of the transfer is obtained with this theory at a significantly lower computational cost as with the quantum generalized Förster theory. Larger deviations between the two theories are expected for large energy gaps as they occur in complexes with chemically different pigments.

Probing the application of kinetic theory to Mg-phyllosilicate growth with Si isotope doping

The Principle of Detailed Balance (PDB) played a defining role in the derivation of the widely-used Transition State Theory rate law equation and serves as an important link between geochemical kinetics and thermodynamics. Although significant improvements have been made in applying the PDB to comparatively simple systems (e.g., SiO2-water), experimental verification of the PDB is lacking for more complex minerals such as the phyllosilicates. Providing kinetic constraints on the rates of phyllosilicate growth from supersaturated solutions is particularly important for constructing facies models, constraining element cycling in the lacustrine and marine environments, and interpreting paleo-biogeochemistry. Here, we use 29Si isotopic doping techniques to quantify the rates of reaction between Mg-phyllosilicate substrates (amorphous Mg-silicate (a talc-like phase) and crystalline talc) and supersaturated solutions at 21 and 60 °C. The results show that the ratio of the forward and backward rates of amorphous Mg-silicate-water reaction approaches unity as the saturation state of the solution approaches the apparent solubility of amorphous Mg-silicate. The precipitation rates coupled with equivalent dissolution rates obtained from experiments with amorphous Mg-silicate substrates appear to obey the same rate function as the precipitation rates coupled with negligible dissolution rates obtained from experiments with crystalline Mg-silicate substrates over the degrees of supersaturation we explore, suggesting that the elementary step limiting the rate of precipitation remains the same. Accordingly, our results demonstrate that the PDB is applicable to amorphous Mg-phyllosilicate-water reactions, thereby reinforcing the use of TST rate equations to describe Mg-phyllosilicate growth. The experimental data can also be taken as evidence that the apparent solubility of amorphous Mg-silicate, a concept previously explained using the kinetic theory of nucleation and growth, also has a thermodynamic meaning, in that it represents a metastable equilibrium with the poorly crystalline phase. The measured, non-negligible forward and backward rates suggest that, even in this metastable state where little if any net reaction is occurring, isotopic signatures can be reset. Moreover, the significant discrepancy between the heterogeneous net growth rates on the amorphous Mg-silicate substrate versus those measured on crystalline talc and sepiolite substrates indicates that mineral crystallinity likely plays a key role in mineral growth during diagenesis.

Analysis of Irreversible Thermodynamic Losses in Emissive-Energy Harvesters Based on Photon Beams

An analysis of irreversible energy losses that happen upon emissive-energy conversion is presented in this article. For this, we show that in these converters, the total amount of entropy produced in the conversion is proportional to the number of emitted photons, which justifies their description as counterparts of thermophotovoltaic engines. In the last part of this article, using a model of low-intensity photon beams and the detailed balance principle, we show the effects of irreversibilities on the output power and efficiency of emissive-energy harvesters.

Plasma screening enhancement of thermonuclear reaction rates

Plasma screening can enhance the thermonuclear reaction rates significantly. The most pronounced effect takes place in the white dwarf cores and neutron star envelopes; there the enhancement factor can reach as tenths orders of magnitude. Here thermodynamically consistent description of this effect, which does not violate of the detailed balance principle, is discussed.

Fundamental Limiting Efficiency and Intrinsic Loss Components of Quantum-Wire Intermediate-Band Solar Cells

Quantum-wire intermediate-band solar cells (QW IBSCs) are good candidates for breaking the Shockley-Queisser limit; however, there are a few studies of them. In this paper, we derive the fundamental limiting efficiency (FLE), the theoretical upper limit of the power-conversion efficiency, for QW IBSCs by calculation of the intrinsic loss. To achieve this, based on a photon-electron detailed-balance principle, the intrinsic loss components (ILCs) are modeled in the QW IBSCs by our considering photon absorption and emission for two transverse directions of confined carriers and for a longitudinal direction of free carriers in the QWs. Furthermore, the ILCs and FLE are investigated in an experimental reported structure of an ${\mathrm{In}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}/\mathrm{Ga}\mathrm{As}$ QW IBSC. For this purpose, the two-dimensional Schr\"odinger equation and the Bloch approximation are used to obtain the placement and width of the intermediate band, respectively. Besides, the effect of changing the indium content, the diagonal length, and the period of QWs, which is a way to engineer the placement and width of the intermediate band and consequently the ILCs and FLE, on the FLE of ${\mathrm{In}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}/\mathrm{Ga}\mathrm{As}$ QW IBSCs is examined.

Solar Thermoradiative-Photovoltaic Energy Conversion

We propose a solar thermal energy conversion system consisting of a solar absorber, a thermoradiative cell or negative illumination photodiode, and a photovoltaic cell. Because it is a heat engine, this system can also be paired with thermal storage to provide reliable electricity generation. Heat from the solar absorber drives radiative recombination current in the thermoradiative cell, and its emitted light is absorbed by the photovoltaic cell to provide an additional photocurrent. Based on the principle of detailed balance, we calculate a limiting solar conversion efficiency of 85% for fully concentrated sunlight and 45% for one sun with an absorber and single-junction cells of equal areas. Ideal and nonideal solar thermoradiative-photovoltaic systems outperform solar thermophotovoltaic converters for low bandgaps and practical absorber temperatures. Their performance enhancement results from a high tolerance to nonradiative generation/recombination and an ability to minimize radiative heat losses. We show that a realistic device with all major losses could achieve increases in solar conversion efficiency by up to 7.9% (absolute) compared to a solar thermophotovoltaic device under low optical concentration. Our results indicate that these converters could serve as efficient heat engines for low cost single axis tracking systems.

Motor-Free Contractility in Active Gels.

Animal cells form contractile structures to promote various functions, from cell motility to cell division. Force generation in these structures is often due to molecular motors such as myosin that require polar substrates for their function. Here, we propose a motor-free mechanism that can generate contraction in biopolymer networks without the need for polarity. This mechanism is based on active binding and unbinding of cross-linkers that breaks the principle of detailed balance, together with the asymmetric force-extension response of semiflexible biopolymers. We find that these two ingredients can generate steady state contraction via a nonthermal, ratchetlike process. We calculate the resulting force-velocity relation using both coarse-grained and microscopic models.

An approach for the measurement of the bulk temperature of single crystal diamond using an X-ray free electron laser

We present a method to determine the bulk temperature of a single crystal diamond sample at an X-Ray free electron laser using inelastic X-ray scattering. The experiment was performed at the high energy density instrument at the European XFEL GmbH, Germany. The technique, based on inelastic X-ray scattering and the principle of detailed balance, was demonstrated to give accurate temperature measurements, within 8% for both room temperature diamond and heated diamond to 500 K. Here, the temperature was increased in a controlled way using a resistive heater to test theoretical predictions of the scaling of the signal with temperature. The method was tested by validating the energy of the phonon modes with previous measurements made at room temperature using inelastic X-ray scattering and neutron scattering techniques. This technique could be used to determine the bulk temperature in transient systems with a temporal resolution of 50 fs and for which accurate measurements of thermodynamic properties are vital to build accurate equation of state and transport models.

Synthetic fluid inclusions XXIII. Effect of temperature and fluid composition on rates of serpentinization of olivine

Serpentinization, i.e. the hydrothermal alteration of ultramafic rocks, is an important and ubiquitous geologic process that occurs at slow- and ultraslow-spreading mid-ocean ridges, magma-poor passive margins, and subduction zones. While serpentinization occurs over a wide temperature range and involves diverse fluid compositions, few experimental studies systematically examined the effects of temperature and fluid composition on the kinetics of serpentinization of olivine, and published rates diverge greatly. We present results of an experimental study using synthetic fluid inclusions in Mg-rich olivine as micro-batch reactors to monitor the effects of temperature (100–350 °C), fluid composition (H2O-MgCl-NaCl, H2O-NaCl, H2O-MgCl), and total salinity on serpentinization rates of olivine under closed system conditions.Petrographic observations and Raman analyses of the experimental run products revealed the alteration of olivine to produce serpentine minerals, brucite, and magnetite. The salinity of the aqueous fluid in the inclusions increased as H2O was removed from the solution and incorporated into the hydrous product phases and served as a proxy for reaction progress. The fastest serpentinization rates were found at 250 °C in the presence of a seawater-like aqueous solution. This result further suggests that serpentinization of olivine is fastest at lower temperatures (∼250 °C) and shallower depths in the oceanic lithosphere than suggested by previous studies (∼300 °C). Moreover, our experiments show that serpentinization rates decrease by several orders of magnitude as salinity and the concentration of dissolved Mg increase. These effects may reconcile some of the differences observed when comparing results of previously published rates obtained from experiments involving fluids of different compositions. We constructed a quantitative model based on the principle of detailed balance to predict variations in serpentinization rates (J±) from low temperatures to 320 °C. It suggests that at 25 °C, serpentinization rates are 4 to 5 orders of magnitude slower than at 250 °C. Moreover, the temperature dependence model has been coupled with the kinetic effects derived from experiments involving different fluid composition to calculate the amount of time required for serpentinization of olivine having different reactive surface areas. The model shows that between 200 and 300 °C serpentinization is fast on geologic timescales when rocks with large reactive surface areas interact with a seawater-like aqueous solution (complete serpentinization in days to decades).