M. Teniou, Mehdi Ramdani, O. Jawad, T. Julien, S. Pannetrat, L. Aberbour
This article introduces a measurement methodology for the evaluation of the specific absorption rate (SAR) of MIMO systems (multiple-input and multiple-output) in which the relative phases between the antennas are rapidly changing and in very short durations. This measurement methodology is enabled by SAR systems that uses vector field measurements combined with a vector spectral analysis of the measured radiofrequency signals for SAR assessment. By exploiting the equivalence principle and the uniqueness of the solution of Maxwell’s equation, the proposed approach allows for an accurate SAR assessment of complex MIMO systems in a very short duration (few seconds).
{"title":"On the measurement procedures for the assessment of the specific absorption rate (SAR) from MIMO cellular-equipment of fast varying relative phases","authors":"M. Teniou, Mehdi Ramdani, O. Jawad, T. Julien, S. Pannetrat, L. Aberbour","doi":"10.5802/CRPHYS.64","DOIUrl":"https://doi.org/10.5802/CRPHYS.64","url":null,"abstract":"This article introduces a measurement methodology for the evaluation of the specific absorption rate (SAR) of MIMO systems (multiple-input and multiple-output) in which the relative phases between the antennas are rapidly changing and in very short durations. This measurement methodology is enabled by SAR systems that uses vector field measurements combined with a vector spectral analysis of the measured radiofrequency signals for SAR assessment. By exploiting the equivalence principle and the uniqueness of the solution of Maxwell’s equation, the proposed approach allows for an accurate SAR assessment of complex MIMO systems in a very short duration (few seconds).","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":"11 1","pages":"1-9"},"PeriodicalIF":1.4,"publicationDate":"2021-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90088282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this contribution, an elasto-viscoplastic fast Fourier transform-based (EVPFFT) numerical implementation of the Mesoscale Field Dislocation Mechanics (MFDM) formulation, called MFDM-EVPFFT, is applied to study the reversible plastic behavior of periodic two-phase crystalline composites with an elastoviscoplastic plastic matrix and a purely elastic second phase. Periodic laminate microstructures of this kind with different periods (i.e. sizes) are considered to examine the size dependence of the Bauschinger effect and hardening during cyclic loading. Comparisons with classic composite effects obtained with conventional crystal plasticity are discussed. Specifically, the MFDM-EVPFFT results shed light on the hardening mechanisms due to piling-up/unpiling-up of geometrically-necessary dislocations (GND) during reverse loading.
{"title":"A numerical study of reversible plasticity using continuum dislocation mechanics","authors":"S. Berbenni, R. Lebensohn","doi":"10.5802/CRPHYS.54","DOIUrl":"https://doi.org/10.5802/CRPHYS.54","url":null,"abstract":"In this contribution, an elasto-viscoplastic fast Fourier transform-based (EVPFFT) numerical implementation of the Mesoscale Field Dislocation Mechanics (MFDM) formulation, called MFDM-EVPFFT, is applied to study the reversible plastic behavior of periodic two-phase crystalline composites with an elastoviscoplastic plastic matrix and a purely elastic second phase. Periodic laminate microstructures of this kind with different periods (i.e. sizes) are considered to examine the size dependence of the Bauschinger effect and hardening during cyclic loading. Comparisons with classic composite effects obtained with conventional crystal plasticity are discussed. Specifically, the MFDM-EVPFFT results shed light on the hardening mechanisms due to piling-up/unpiling-up of geometrically-necessary dislocations (GND) during reverse loading.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":"11 24 1","pages":"1-18"},"PeriodicalIF":1.4,"publicationDate":"2021-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79586375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nonlinear phononics is the phenomenon in which a coherent dynamics in a material along a set of phonons is launched after its infrared-active phonons are selectively excited using external light pulses. The microscopic mechanism underlying this phenomenon is the nonlinear coupling of the pumped infrared-active mode to other phonon modes present in a material. Nonlinear phonon couplings can cause finite time-averaged atomic displacements with or without broken crystal symmetries depending on the order, magnitude and sign of the nonlinearities. Such coherent lattice displacements along phonon coordinates can be used to control the physical properties of materials and even induce transient phases with lower symmetries. Light-control of materials via nonlinear phononics has become a practical reality due to the availability of intense mid-infrared lasers that can drive large-amplitude oscillations of the infrared-active phonons of materials. Mid-infrared pump induced insulator-metal transitions and spin and orbital order melting have been observed in pump-probe experiments. First principles based microscopic theory of nonlinear phononics has been developed, and it has been used to better understand how the lattice evolves after a mid-infrared pump excitation of infrared-active phonons. This theory has been used to predict light-induced switching of ferroelectric polarization as well as ferroelectricity in paraelectrics and ferromagnetism in antiferromagnets, which have been partially confirmed in recent experiments. This review summarizes the experimental and theoretical developments within this emerging field.
{"title":"Light-control of materials via nonlinear phononics","authors":"A. Subedi","doi":"10.5802/crphys.44","DOIUrl":"https://doi.org/10.5802/crphys.44","url":null,"abstract":"Nonlinear phononics is the phenomenon in which a coherent dynamics in a material along a set of phonons is launched after its infrared-active phonons are selectively excited using external light pulses. The microscopic mechanism underlying this phenomenon is the nonlinear coupling of the pumped infrared-active mode to other phonon modes present in a material. Nonlinear phonon couplings can cause finite time-averaged atomic displacements with or without broken crystal symmetries depending on the order, magnitude and sign of the nonlinearities. Such coherent lattice displacements along phonon coordinates can be used to control the physical properties of materials and even induce transient phases with lower symmetries. Light-control of materials via nonlinear phononics has become a practical reality due to the availability of intense mid-infrared lasers that can drive large-amplitude oscillations of the infrared-active phonons of materials. Mid-infrared pump induced insulator-metal transitions and spin and orbital order melting have been observed in pump-probe experiments. First principles based microscopic theory of nonlinear phononics has been developed, and it has been used to better understand how the lattice evolves after a mid-infrared pump excitation of infrared-active phonons. This theory has been used to predict light-induced switching of ferroelectric polarization as well as ferroelectricity in paraelectrics and ferromagnetism in antiferromagnets, which have been partially confirmed in recent experiments. This review summarizes the experimental and theoretical developments within this emerging field.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45491500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The weakest link theory, sometimes proposed to analyze size effects on the plastic behaviour of single crystals, is introduced in 3D numerical simulations of polycrystals. The approach relies on a random distribution of sources in space and strength associated to a crystal plasticity law with constant per layer Critical Resolved Shear Stresses (CRSS). It is able to reproduce: (1) the grain size dependence of the yield stress given by the Hall–Petch law, (2) intense slip band localization patterns as often observed at the grains surface, especially pronounced in quenched or irradiated metals, but difficult to reproduce by numerical simulation.
{"title":"Grain size effects and weakest link theory in 3D crystal plasticity simulations of polycrystals","authors":"L. Gélébart","doi":"10.5802/CRPHYS.53","DOIUrl":"https://doi.org/10.5802/CRPHYS.53","url":null,"abstract":"The weakest link theory, sometimes proposed to analyze size effects on the plastic behaviour of single crystals, is introduced in 3D numerical simulations of polycrystals. The approach relies on a random distribution of sources in space and strength associated to a crystal plasticity law with constant per layer Critical Resolved Shear Stresses (CRSS). It is able to reproduce: (1) the grain size dependence of the yield stress given by the Hall–Petch law, (2) intense slip band localization patterns as often observed at the grains surface, especially pronounced in quenched or irradiated metals, but difficult to reproduce by numerical simulation.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":"90 1","pages":"1-18"},"PeriodicalIF":1.4,"publicationDate":"2021-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87727593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Disordered materials, like metallic glasses or silicate glasses, have an atomistic amorphous structure preventing the formation of extended defects such as dislocations. Irreversible deformation in these materials is thus localized, but can organize along shear bands. In this brief review, based on recent publications, we will see if local plasticity can be measured and predicted in disordered atomic assemblies, and in what conditions it can be related to preexisting structural defects. We will then draw a general picture of the plastic mechanical behaviour within the theoretical framework of mechanical instabilities. Finally, we will focus our attention on different scenarii for shear banding in glasses.
{"title":"Elasto-plastic behavior of amorphous materials: a brief review","authors":"A. Tanguy","doi":"10.5802/CRPHYS.49","DOIUrl":"https://doi.org/10.5802/CRPHYS.49","url":null,"abstract":"Disordered materials, like metallic glasses or silicate glasses, have an atomistic amorphous structure preventing the formation of extended defects such as dislocations. Irreversible deformation in these materials is thus localized, but can organize along shear bands. In this brief review, based on recent publications, we will see if local plasticity can be measured and predicted in disordered atomic assemblies, and in what conditions it can be related to preexisting structural defects. We will then draw a general picture of the plastic mechanical behaviour within the theoretical framework of mechanical instabilities. Finally, we will focus our attention on different scenarii for shear banding in glasses.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":"40 1","pages":"1-17"},"PeriodicalIF":1.4,"publicationDate":"2021-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77371510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Pardoen, Nathan Klavzer, S. Gayot, F. Loock, J. Chevalier, X. Morelle, Vincent Destoop, F. Lani, P. Camanho, L. Brassart, B. Nysten, C. Bailly
Tremendous progress in nanomechanical testing and modelling has been made during the last two decades. This progress emerged from different areas of materials science dealing with the mechanical behaviour of thin films and coatings, polymer blends, nanomaterials or microstructure constituents as well as from the rapidly growing field of MEMS. Nanomechanical test methods include, among others, nanoindentation, in-situ testing in a scanning or transmission electron microscope coupled with digital image correlation, atomic force microscopy with new advanced dynamic modes, micropillar compression or splitting, on-chip testing, or notched microbeam bending. These methods, when combined, reveal the elastic, plastic, creep, and fracture properties at the microand even the nanoscale. Modelling techniques including atomistic simulations and several coarse graining methods have been enriched to a level that allows treating complex size, interface or surface effects in a realistic way. Interestingly, the transfer of this paradigm to advanced long fibre-reinforced polymer composites has not been as intense compared to other fields. Here, we show that these methods put together can offer new perspectives for an improved characterisation of the response at the elementary fibre-matrix level, involving the interfaces and interphases. Yet, there are still many open issues left to resolve. In addition, this is the length scale, typically below 10 micrometres, ∗Corresponding author. ISSN (electronic) : 1878-1535 https://comptes-rendus.academie-sciences.fr/physique/
{"title":"Nanomechanics serving polymer-based composite research","authors":"T. Pardoen, Nathan Klavzer, S. Gayot, F. Loock, J. Chevalier, X. Morelle, Vincent Destoop, F. Lani, P. Camanho, L. Brassart, B. Nysten, C. Bailly","doi":"10.5802/CRPHYS.56","DOIUrl":"https://doi.org/10.5802/CRPHYS.56","url":null,"abstract":"Tremendous progress in nanomechanical testing and modelling has been made during the last two decades. This progress emerged from different areas of materials science dealing with the mechanical behaviour of thin films and coatings, polymer blends, nanomaterials or microstructure constituents as well as from the rapidly growing field of MEMS. Nanomechanical test methods include, among others, nanoindentation, in-situ testing in a scanning or transmission electron microscope coupled with digital image correlation, atomic force microscopy with new advanced dynamic modes, micropillar compression or splitting, on-chip testing, or notched microbeam bending. These methods, when combined, reveal the elastic, plastic, creep, and fracture properties at the microand even the nanoscale. Modelling techniques including atomistic simulations and several coarse graining methods have been enriched to a level that allows treating complex size, interface or surface effects in a realistic way. Interestingly, the transfer of this paradigm to advanced long fibre-reinforced polymer composites has not been as intense compared to other fields. Here, we show that these methods put together can offer new perspectives for an improved characterisation of the response at the elementary fibre-matrix level, involving the interfaces and interphases. Yet, there are still many open issues left to resolve. In addition, this is the length scale, typically below 10 micrometres, ∗Corresponding author. ISSN (electronic) : 1878-1535 https://comptes-rendus.academie-sciences.fr/physique/","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":"12 1","pages":"1-22"},"PeriodicalIF":1.4,"publicationDate":"2021-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77745621","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In many quantum materials, strong electron correlations lead to the emergence of new states of matter. In particular, the study in the last decades of the complex phase diagram of high temperature superconducting cuprates highlighted intra-unit-cell electronic instabilities breaking discrete Ising-like symmetries, while preserving the lattice translation invariance. Polarized neutron diffraction experiments have provided compelling evidences supporting a new form of intra-unit-cell magnetism, emerging concomitantly with the so-called pseudogap state of these materials. This observation is currently interpreted as the magnetic hallmark of an intra-unit-cell loop current order, breaking both parity and time-reversal symmetries. More generally, this magneto-electric state is likely to exist in a wider class of quantum materials beyond superconducting cuprates. For instance, it has been already observed in hole-doped Mott insulating iridates or in the spin liquid state of hole-doped 2-leg ladder cuprates.
{"title":"Loop currents in quantum matter","authors":"P. Bourges, D. Bounoua, Y. Sidis","doi":"10.5802/crphys.84","DOIUrl":"https://doi.org/10.5802/crphys.84","url":null,"abstract":"In many quantum materials, strong electron correlations lead to the emergence of new states of matter. In particular, the study in the last decades of the complex phase diagram of high temperature superconducting cuprates highlighted intra-unit-cell electronic instabilities breaking discrete Ising-like symmetries, while preserving the lattice translation invariance. Polarized neutron diffraction experiments have provided compelling evidences supporting a new form of intra-unit-cell magnetism, emerging concomitantly with the so-called pseudogap state of these materials. This observation is currently interpreted as the magnetic hallmark of an intra-unit-cell loop current order, breaking both parity and time-reversal symmetries. More generally, this magneto-electric state is likely to exist in a wider class of quantum materials beyond superconducting cuprates. For instance, it has been already observed in hole-doped Mott insulating iridates or in the spin liquid state of hole-doped 2-leg ladder cuprates.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45094282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We compare the macroscopic and the local plastic behavior of a model amorphous solid based on two radically different numerical descriptions. On the one hand, we simulate glass samples by atomistic simulations. On the other, we implement a mesoscale elasto-plastic model based on a solid-mechanics description. The latter is extended to consider the anisotropy of the yield surface via statistically distributed local and discrete weak planes on which shear transformations can be activated. To make the comparison as quantitative as possible, we consider the simple case of a quasistatically driven two-dimensional system in the stationary flow state and compare mechanical observables measured on both models over the same length scales. We show that the macroscale response, including its fluctuations, can be quantitatively recovered for a range of elasto-plastic mesoscale parameters. Using a newly developed method that makes it possible to probe the local yield stresses in atomistic simulations, we calibrate the local mechanical response of the elasto-plastic model at different coarse-graining scales. In this case, the calibration shows a qualitative agreement only for an optimized subset of mesoscale parameters and for sufficiently coarse probing length scales. This calibration allows us to establish a length scale for the mesoscopic elements that corresponds to an upper bound of the shear transformation size, a key physical parameter in elasto-plastic models. We find that certain properties naturally emerge from the elasto-plastic model. In particular, we show that the elasto-plastic model reproduces the Bauschinger effect, namely the plasticity-induced anisotropy in the stress-strain response. We discuss the successes and failures of our approach, the impact of different model ingredients and propose future research directions for quantitative multi-scale models of amorphous plasticity.
{"title":"Insights from the quantitative calibration of an elasto-plastic model from a Lennard-Jones atomic glass","authors":"D. F. Castellanos, S. Roux, S. Patinet","doi":"10.5802/CRPHYS.48","DOIUrl":"https://doi.org/10.5802/CRPHYS.48","url":null,"abstract":"We compare the macroscopic and the local plastic behavior of a model amorphous solid based on two radically different numerical descriptions. On the one hand, we simulate glass samples by atomistic simulations. On the other, we implement a mesoscale elasto-plastic model based on a solid-mechanics description. The latter is extended to consider the anisotropy of the yield surface via statistically distributed local and discrete weak planes on which shear transformations can be activated. To make the comparison as quantitative as possible, we consider the simple case of a quasistatically driven two-dimensional system in the stationary flow state and compare mechanical observables measured on both models over the same length scales. We show that the macroscale response, including its fluctuations, can be quantitatively recovered for a range of elasto-plastic mesoscale parameters. Using a newly developed method that makes it possible to probe the local yield stresses in atomistic simulations, we calibrate the local mechanical response of the elasto-plastic model at different coarse-graining scales. In this case, the calibration shows a qualitative agreement only for an optimized subset of mesoscale parameters and for sufficiently coarse probing length scales. This calibration allows us to establish a length scale for the mesoscopic elements that corresponds to an upper bound of the shear transformation size, a key physical parameter in elasto-plastic models. We find that certain properties naturally emerge from the elasto-plastic model. In particular, we show that the elasto-plastic model reproduces the Bauschinger effect, namely the plasticity-induced anisotropy in the stress-strain response. We discuss the successes and failures of our approach, the impact of different model ingredients and propose future research directions for quantitative multi-scale models of amorphous plasticity.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48567159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In heterobilayers of 2D semiconductors, moiré pattern forms due to the inevitable lattice mismatch and twisting. Earlier works have shown that interlayer excitons in long-period moiré pattern experience a pronounced superlattice potential and have nanoscale patterned light-coupling properties. This leads to remarkable new possibilities to explore exciton physics and tailor optical properties. Line defects such as twin domain boundaries are commonly found in semiconducting transition metal dichalcogenides monolayer, which, in the context of a heterobilayer, leads to an interface between the R-stacking moiré and H-stacking moiré. Here, we show that such interface created by twin-domain boundary realizes a line-defect in the moiré superlattices for interlayer excitons, which localises a one-dimensional exciton mode of topological origin. The defect configuration in the moiré exciton superlattices can be continuously tuned by the interlayer translation and twisting angle, and is also a reflection of the atomic configuration of the domain boundary. The dispersion, wavefunction, and light coupling properties of the interface exciton modes are investigated at different superlattice defect configurations.
{"title":"Moiré excitons at line defects in transition metal dichalcogenides heterobilayers","authors":"Jianju Tang, Hongyi Yu, C. Shih, W. Yao","doi":"10.5802/CRPHYS.50","DOIUrl":"https://doi.org/10.5802/CRPHYS.50","url":null,"abstract":"In heterobilayers of 2D semiconductors, moiré pattern forms due to the inevitable lattice mismatch and twisting. Earlier works have shown that interlayer excitons in long-period moiré pattern experience a pronounced superlattice potential and have nanoscale patterned light-coupling properties. This leads to remarkable new possibilities to explore exciton physics and tailor optical properties. Line defects such as twin domain boundaries are commonly found in semiconducting transition metal dichalcogenides monolayer, which, in the context of a heterobilayer, leads to an interface between the R-stacking moiré and H-stacking moiré. Here, we show that such interface created by twin-domain boundary realizes a line-defect in the moiré superlattices for interlayer excitons, which localises a one-dimensional exciton mode of topological origin. The defect configuration in the moiré exciton superlattices can be continuously tuned by the interlayer translation and twisting angle, and is also a reflection of the atomic configuration of the domain boundary. The dispersion, wavefunction, and light coupling properties of the interface exciton modes are investigated at different superlattice defect configurations.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":"61 1","pages":"1-16"},"PeriodicalIF":1.4,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91236565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Agathangelou, P. Roy, M. D. C. Marín, N. Ferré, M. Olivucci, T. Buckup, J. Léonard, S. Haacke
Sub-picosecond photo-isomerization is the major primary process of energy conversion in retinal proteins and has as such been in the focus of extensive theoretical and experimental work over the past decades. In this review article, we revisit the long-standing question as to how the protein tunes the isomerization speed and quantum yield. We focus on our recent contributions to this field, which underscore the concept of a delicate mixing of reactive and non-reactive excited states, as a result of steric properties and electrostatic interactions with the protein environment. Further avenues and new approaches are outlined which hold promise for advancing our understanding of these intimately coupled chromophore-protein systems.
{"title":"Sub-picosecond C=C bond photo-isomerization: evidence for the role of excited state mixing","authors":"D. Agathangelou, P. Roy, M. D. C. Marín, N. Ferré, M. Olivucci, T. Buckup, J. Léonard, S. Haacke","doi":"10.5802/CRPHYS.41","DOIUrl":"https://doi.org/10.5802/CRPHYS.41","url":null,"abstract":"Sub-picosecond photo-isomerization is the major primary process of energy conversion in retinal proteins and has as such been in the focus of extensive theoretical and experimental work over the past decades. In this review article, we revisit the long-standing question as to how the protein tunes the isomerization speed and quantum yield. We focus on our recent contributions to this field, which underscore the concept of a delicate mixing of reactive and non-reactive excited states, as a result of steric properties and electrostatic interactions with the protein environment. Further avenues and new approaches are outlined which hold promise for advancing our understanding of these intimately coupled chromophore-protein systems.","PeriodicalId":50650,"journal":{"name":"Comptes Rendus Physique","volume":" ","pages":""},"PeriodicalIF":1.4,"publicationDate":"2021-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42953079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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