scholarly journals Ultrafast imaging of spontaneous symmetry breaking in a photoionized molecular system

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Min Li ◽  
Ming Zhang ◽  
Oriol Vendrell ◽  
Zhenning Guo ◽  
Qianru Zhu ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Molecular System ◽  
Ultrafast Dynamics ◽  
Quantum Molecular Dynamics ◽  
Ultrafast Imaging ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Dynamics Simulations ◽  
Symmetry Space

AbstractThe Jahn-Teller effect is an essential mechanism of spontaneous symmetry breaking in molecular and solid state systems, and has far-reaching consequences in many fields. Up to now, to directly image the onset of Jahn-Teller symmetry breaking remains unreached. Here we employ ultrafast ion-coincidence Coulomb explosion imaging with sub-10 fs resolution and unambiguously image the ultrafast dynamics of Jahn-Teller deformations of $${{\rm{CH}}}_{4}^{+}$$ CH 4 + cation in symmetry space. It is unraveled that the Jahn-Teller deformation from C3v to C2v geometries takes a characteristic time of 20 ± 7 fs for this system. Classical and quantum molecular dynamics simulations agree well with the measurement, and reveal dynamics for the build-up of the C2v structure involving complex revival process of multiple vibrational pathways of the $${{\rm{CH}}}_{4}^{+}$$ CH 4 + cation.

scholarly journals Ultrafast imaging of spontaneous symmetry breaking in a photoionized molecular system

2020 ◽  
Author(s):  
Min Li ◽  
Ming Zhang ◽  
Oriol Vendrell ◽  
Zhenning Guo ◽  
Qianru Zhu ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Molecular System ◽  
Real Space ◽  
Ultrafast Dynamics ◽  
Quantum Molecular Dynamics ◽  
Ultrafast Imaging ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Dynamics Simulations

Abstract The Jahn-Teller effect is an essential mechanism of spontaneous symmetry breaking in molecular and solid state systems, and has far-reaching consequences in many fields. Up to now, to direct image the onset of Jahn-Teller symmetry breaking remains unreached. Employing ultrafast ion-coincidence Coulomb explosion imaging with sub-10 fs resolution, we unambiguously imaged the ultrafast dynamics of Jahn-Teller deformations of CH4+ cation in real space. It is unraveled that the Jahn-Teller deformation from C3v to C2v geometries takes a characteristic time of about 20 femtoseconds for this system. Classical and quantum molecular dynamics simulations agree well with the measurement, and reveal dynamics for the build-up of the C2v structure involving complex phasing process of multiple vibrational pathways of the CH4+ cation.

Symmetry breaking in the planar configurations of disilicon tetrahalides: Pseudo-Jahn–Teller effect parameters, hardness and electronegativity

2015 ◽  
Vol 17 (43) ◽  
pp. 29251-29261 ◽  
Author(s):  
Ghazaleh Kouchakzadeh ◽  
Davood Nori-Shargh
Keyword(s):  
Symmetry Breaking ◽  
Ab Initio ◽  
Teller Effect ◽  
Dft Methods ◽  
Jahn Teller ◽  
Jahn Teller Effect

The correlations between the Pseudo-Jahn–Teller Effect (PJTE) parameters (i.e. F, Δ and K0), structural and configurational properties, global hardness and global electronegativities in disilicon tetrahalides were investigated by means of ab initio and hybrid-DFT methods.

Symmetry breaking in the axial symmetrical configurations of enolic propanedial, propanedithial, and propanediselenal: pseudo Jahn–Teller effect versus the resonance-assisted hydrogen bond theory

2015 ◽  
Vol 93 (6) ◽  
pp. 673-684 ◽  
Author(s):  
Elahe Jalali ◽  
Davood Nori-Shargh
Keyword(s):  
Density Functional Theory ◽  
Hydrogen Bond ◽  
Symmetry Breaking ◽  
Density Functional ◽  
Teller Effect ◽  
Electron Delocalization ◽  
Functional Theory ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Resonance Assisted Hydrogen Bond

The origin of the symmetry breaking in the axial symmetrical configurations of enolic propanedial (1), propanedithial (2), and propanediselenal (3) have been investigated by means of time-dependence density functional theory and natural bond orbital interpretations. The results obtained at the quantum chemistry composite (G2MP2, CBS-QB3), ab initio molecular orbital (MP2/6-311++G**), and hybrid density functional theory (B3LYP/6-311++G**) levels of theory showed that the hydrogen-centered synchronous axial symmetrical (C2v) configurations of compounds 1–3 possessing the maximum π-electron delocalization within the M1=C2–C3=C4–M5–H6 keto-enol groups are less stable than their corresponding plane symmetrical (Cs) forms. Importantly, the symmetry breaking in the C2v configurations of the enol forms of compounds 1–3 to their corresponding plane symmetrical Cs configurations is due to the pseudo Jahn–Teller effect (PJTE) by mixing the ground A1 and excited B2 electronic states resulting in a PJT (A1 + B2) ⊗ b2 problem. We may expect that by the decrease of the energy gaps between reference states in the C2v forms that are involved in the PJTE decrease from compound 1 to compound 3, the PJT stabilization energy (PJTSE) may increase but the results obtained showed that the corresponding PJTSEs decrease. This fact can be justified by the increase of the electron delocalizations from the nonbonding orbitals of the C=M moieties to the antibonding orbitals of the H–M bonds, which leads to an increase of the π-electron delocalization within the M1=C2–C3=C4–M5–H6 keto-enol groups. In confrontation between the impacts of the resonance-assisted hydrogen bond and PJTE in the structural and configurational properties of compounds 1–3, PJTE has an overwhelming contribution and causes the symmetry breaking of the C2v configurations to their corresponding Cs forms. The correlations between the structural parameters, synchronicity indices, natural charges, PJTSEs, electron delocalizations, and the hardness of compounds 1–3 have been investigated.

scholarly journals The Jahn–Teller and Pseudo-Jahn–Teller Effects: A Unique and Only Source of Spontaneous Symmetry Breaking in Atomic Matter

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1577
Author(s):  
Isaac B. Bersuker
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
External Perturbation ◽  
Broken Symmetry ◽  
High Symmetry ◽  
Atomic Systems ◽  
Jahn Teller ◽  
Curie Principle ◽  
Adiabatic Potential Energy Surface ◽  
Definition Of

In a mostly review paper, we show that the important problem of symmetry, broken symmetry, and spontaneous broken symmetry of polyatomic systems is directly related to the Jahn–Teller (JT) and pseudo-Jahn–Teller (PJT) effects, including the hidden-JT and hidden-PJT effects, and these JT effects (JTEs) are the only source of spontaneous symmetry breaking in matter. They are directly related to the violation of the adiabatic approximation by the vibronic and other nonadiabatic couplings (jointly termed nonadiabaticity) in the interaction between the electrons and nuclei, which becomes significant in the presence of two or more degenerate or pseudodegenerate electronic states. In a generalization of this understanding of symmetry, we suggest an improved (quantum) definition of stereo-chemical polyatomic space configuration, in which, starting with their high-symmetry configuration, we separate all atomic systems into three distinguishable groups: (1) weak nonadiabaticity, stable high-symmetry configurations; (2) moderate-to-strong nonadiabaticity, unstable high-symmetry configurations, JTEs, spontaneous symmetry breaking (SSB); (3) very strong nonadiabaticity, stable distorted configurations. The JTEs, inherent to the second group of systems, produce a rich variety of novel properties, based on their multiminimum adiabatic potential energy surface (APES), leading to a short lifetime in the distorted configuration. We show the role of the Curie principle in the possibilities to observe the SSB in atomic matter, and mention briefly the revealed recently gamma of novel properties of matter in its interaction with external perturbation that occur due to the SSB, including ferroelectricity and orientational polarization, leading to enhanced permittivity and flexoelectricity.

scholarly journals Actuation of magnetoelastic membranes in precessing magnetic fields

2019 ◽  
Vol 116 (7) ◽  
pp. 2500-2505 ◽  
Author(s):  
Chase Austyn Brisbois ◽  
Mykola Tasinkevych ◽  
Pablo Vázquez-Montejo ◽  
Monica Olvera de la Cruz
Keyword(s):  
Molecular Dynamics ◽  
Magnetic Fields ◽  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Continuum Mechanics ◽  
Superparamagnetic Nanoparticles ◽  
Magnetic Interactions ◽  
Robotic Systems ◽  
Elastic Media ◽  
Dynamics Simulations

Superparamagnetic nanoparticles incorporated into elastic media offer the possibility of creating actuators driven by external fields in a multitude of environments. Here, magnetoelastic membranes are studied through a combination of continuum mechanics and molecular dynamics simulations. We show how induced magnetic interactions affect the buckling and the configuration of magnetoelastic membranes in rapidly precessing magnetic fields. The field, in competition with the bending and stretching of the membrane, transmits forces and torques that drives the membrane to expand, contract, or twist. We identify critical field values that induce spontaneous symmetry breaking as well as field regimes where multiple membrane configurations may be observed. Our insights into buckling mechanisms provide the bases to develop soft, autonomous robotic systems that can be used at micro- and macroscopic length scales.

Ultrafast dynamics in LMCT and intraconfigurational excited states in hexahaloiridates(iv), models for heavy transition metal complexes and building blocks of quantum correlated materials

2020 ◽  
Vol 22 (30) ◽  
pp. 17351-17364
Author(s):  
Darya S. Budkina ◽  
Firew T. Gemeda ◽  
Sergey M. Matveev ◽  
Alexander N. Tarnovsky
Keyword(s):  
Excited States ◽  
Transition Metal Complexes ◽  
Electronic States ◽  
Building Blocks ◽  
Ultrafast Dynamics ◽  
Relaxation Dynamics ◽  
Excited Electronic States ◽  
Ultrafast Relaxation ◽  
Jahn Teller ◽  
Jahn Teller Effect

Two heavy octahedral Ir(iv) halides in intraconfigurational and LMCT excited electronic states with ultrafast relaxation dynamics driven by the Jahn–Teller effect.

scholarly journals Ultrafast dynamics with the exact factorization

2021 ◽  
Vol 94 (9) ◽  
Author(s):  
Federica Agostini ◽  
E. K. U. Gross
Keyword(s):  
Time Dependent ◽  
Ultrafast Dynamics ◽  
Quantum Molecular Dynamics ◽  
Spin Orbit Coupling ◽  
Ultrafast Processes ◽  
Dissociation Dynamics ◽  
Dynamics Simulations ◽  
Exact Factorization ◽  
External Time ◽  
Dependent Field

Abstract The exact factorization of the time-dependent electron–nuclear wavefunction has been employed successfully in the field of quantum molecular dynamics simulations for interpreting and simulating light-induced ultrafast processes. In this work, we summarize the major developments leading to the formulation of a trajectory-based approach, derived from the exact factorization equations, capable of dealing with nonadiabatic electronic processes, and including spin-orbit coupling and the non-perturbative effect of an external time-dependent field. This trajectory-based quantum-classical approach has been dubbed coupled-trajectory mixed quantum-classical (CT-MQC) algorithm, whose performance is tested here to study the photo-dissociation dynamics of IBr. Graphic abstract

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