Eli Pollak
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View article: The effect of an optical cavity on diabatic tunneling in an ensemble of symmetric double-well systems
The effect of an optical cavity on diabatic tunneling in an ensemble of symmetric double-well systems Open
The vacuum field of an optical cavity can potentially modify chemical reactivity and other dynamical properties via vibrational strong coupling (VSC). This intriguing finding has inspired numerous studies, but the underlying mechanisms rem…
View article: Semiclassical second order vibrational perturbation theory for hopping rates of H and D atoms on Pt(111) and H on Ru(0001)
Semiclassical second order vibrational perturbation theory for hopping rates of H and D atoms on Pt(111) and H on Ru(0001) Open
Wolynes's theory for tunneling in dissipative systems, constructed for parabolic barriers is generalized to obtain hopping rates of H and D atoms on metal surfaces.
View article: Theory of Nonadiabatic Tunneling Splitting
Theory of Nonadiabatic Tunneling Splitting Open
Estimating tunneling splittings is a long-standing quantum mechanical challenge for theoretical methods. Sometimes splittings are so small, i.e., within a fraction of a wavenumber, pushing the limits of experimental detection and computati…
View article: Modified vibrational perturbation theory as applied to the collinear H + H2 and D + H2 reactions
Modified vibrational perturbation theory as applied to the collinear H + H2 and D + H2 reactions Open
A multidimensional version of the modification to vibrational perturbation theory is developed in this article. The modifications to the action are of two types: one is by shifting the energy scale with the VPT2 zero point energy E0 (mVPT2…
View article: Is Quantum Above-Barrier Reflection Important for Molecular Barrier Crossing Rates?
Is Quantum Above-Barrier Reflection Important for Molecular Barrier Crossing Rates? Open
Understanding quantum tunneling and above-barrier reflection effects on unimolecular and bimolecular reaction rate constants remains challenging to this very day. In many applications, especially when considering moderate-to-high temperatu…
View article: A note on vibrational perturbation theory for tunneling splitting in a symmetric double well potential
A note on vibrational perturbation theory for tunneling splitting in a symmetric double well potential Open
The modified version of second and fourth order vibrational perturbation theory, whereby the Euclidean action for tunneling is computed on the inverted potential at a shifted energy that is ℏ2 dependent, is applied to a symmetric double we…
View article: <i>ℏ</i> 4 quantum corrections to semiclassical transmission probabilities
<i>ℏ</i> 4 quantum corrections to semiclassical transmission probabilities Open
The combination of vibrational perturbation theory with the replacement of the harmonic oscillator quantization condition along the reaction coordinate with an imaginary action to be used in the uniform semiclassical approximation for the …
View article: A personal perspective of the present status and future challenges facing thermal reaction rate theory
A personal perspective of the present status and future challenges facing thermal reaction rate theory Open
Reaction rate theory has been at the center of physical chemistry for well over one hundred years. The evolution of the theory is not only of historical interest. Reliable and accurate computation of reaction rates remains a challenge to t…
View article: <i>ℏ</i><sup>2</sup> Corrections to Semiclassical Transmission Coefficients
<i>ℏ</i><sup>2</sup> Corrections to Semiclassical Transmission Coefficients Open
The uniform semiclassical expression for the energy-dependent transmission probability through a barrier has been a staple of reaction rate theory for almost 90 years. Yet, when using the classical Euclidean action, the transmission probab…
View article: Erratum: Thermal rate of transmission through a barrier: Exact expansion of up to and including terms of order <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mi>ℏ</mml:mi><mml:mn>4</mml:mn></mml:msup></mml:math> [Phys. Rev. A <b>107</b>, 022203 (2023)]
Erratum: Thermal rate of transmission through a barrier: Exact expansion of up to and including terms of order [Phys. Rev. A <b>107</b>, 022203 (2023)] Open
Received 19 February 2024DOI:https://doi.org/10.1103/PhysRevA.109.039901©2024 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasAtomic & molecular collisionsChemical reactionsClassical mechanicsScattering of atoms, mol…
View article: Grazing incidence fast atom diffraction: general considerations, semiclassical perturbation theory and experimental implications
Grazing incidence fast atom diffraction: general considerations, semiclassical perturbation theory and experimental implications Open
Semiclassical methods are used to describe grazing incidence scattering of fast atoms (GIFAD) from surfaces. Our analytical results illuminate the origin of GIFAD phenomena and describe experiments quantitatively.
View article: Multidimensional uniform semiclassical instanton thermal rate theory
Multidimensional uniform semiclassical instanton thermal rate theory Open
Instanton-based rate theory is a powerful tool that is used to explore tunneling in many-dimensional systems. Yet, it diverges at the so-called “crossover temperature.” Using the uniform semiclassical transmission probability of Kemble [Ph…
View article: Uniform Semiclassical Instanton Rate Theory
Uniform Semiclassical Instanton Rate Theory Open
The instanton expression for the thermal transmission probability through a one-dimensional barrier is derived by using the uniform semiclassical energy-dependent transmission coefficient of Kemble. The resulting theory does not diverge at…
View article: Cavity-Induced Quantum Interference and Collective Interactions in van der Waals Systems
Cavity-Induced Quantum Interference and Collective Interactions in van der Waals Systems Open
The central topic of this letter is to show that light-matter hybridization not only gives rise to novel dynamic responses but can also modify intermolecular interactions and induce new structural order. Using the van der Waals (vdW) syste…
View article: Recent Developments in Kramers’ Theory of Reaction Rates
Recent Developments in Kramers’ Theory of Reaction Rates Open
In this short review, we provide an update of recent developments in Kramers’ theory of reaction rates. After a brief introduction stressing the importance of this theory initially developed for chemical reactions, we briefly present the m…
View article: Comparison of physical processes of atom-surface scattering computed by classical and quantum dynamics
Comparison of physical processes of atom-surface scattering computed by classical and quantum dynamics Open
We have performed classical and quantum dynamical simulations to calculate dynamical quantities for physical processes of atom - surface scattering, e.g., trapping probability and average energy loss, final angular distribution of a partic…
View article: Lower bounds on par with upper bounds for few-electron atomic energies
Lower bounds on par with upper bounds for few-electron atomic energies Open
The development of computational resources has made it possible to determine upper bounds for atomic and molecular energies with high precision. Yet, error bounds to the computed energies have been available only as estimates. In this pape…
View article: Reply to the ‘Comment on “Perturbation theory of scattering for grazing-incidence fast-atom diffraction”’ by G. A. Bocan, H. Breiss, S. Szilasi, A. Momeni, E. M. S. Casagrande, E. A. Sánchez, M. S. Gravielle and H. Khemliche, <i>Phys. Chem. Chem. Phys.</i>, 2023, <b>25</b>, DOI: 10.1039/D3CP02486E
Reply to the ‘Comment on “Perturbation theory of scattering for grazing-incidence fast-atom diffraction”’ by G. A. Bocan, H. Breiss, S. Szilasi, A. Momeni, E. M. S. Casagrande, E. A. Sánchez, M. S. Gravielle and H. Khemliche, <i>Phys. Chem. Chem. Phys.</i>, 2023, <b>25</b>, DOI: 10.1039/D3CP02486E Open
Perturbation theory, in first order, fits experiment as well as DFT-based potentials suggesting modulation of the well-depth across the scattering channel contributes to observed changes in the rainbow angle.
View article: Nonadiabatic Couplings Can Speed Up Quantum Tunneling Transition Path Times
Nonadiabatic Couplings Can Speed Up Quantum Tunneling Transition Path Times Open
Quantum tunneling is known to play an important role in the dynamics of systems with nonadiabatic couplings. However, until recently, the time-domain properties of nonadiabatic scattering have been severely under-explored. Using numericall…
View article: The Effect of Time Resolution on Apparent Transition Path Times Observed in Single-Molecule Studies of Biomolecules
The Effect of Time Resolution on Apparent Transition Path Times Observed in Single-Molecule Studies of Biomolecules Open
Single-molecule experiments have now achieved a time resolution allowing observation of transition paths, the brief trajectory segments where the molecule undergoing an unfolding or folding transition enters the energetically or entropical…
View article: ℏ2 expansion of the transmission probability through a barrier
ℏ2 expansion of the transmission probability through a barrier Open
Ninety years ago, Wigner derived the leading order expansion term in ℏ2 for the tunneling rate through a symmetric barrier. His derivation included two contributions: one came from the parabolic barrier, but a second term involved the four…
View article: Transition Path Flight Times and Nonadiabatic Electronic Transitions
Transition Path Flight Times and Nonadiabatic Electronic Transitions Open
Transition path flight times are studied for scattering on two electronic surfaces with a single crossing. These flight times reveal nontrivial quantum effects such as resonance lifetimes and nonclassical passage times and reveal that nona…
View article: Coherent state representation of thermal correlation functions with applications to rate theory
Coherent state representation of thermal correlation functions with applications to rate theory Open
A coherent state phase space representation of operators, based on the Husimi distribution, is used to derive an exact expression for the symmetrized version of thermal correlation functions. In addition to the time and temperature indepen…
View article: Perturbation theory of scattering for grazing-incidence fast-atom diffraction
Perturbation theory of scattering for grazing-incidence fast-atom diffraction Open
A classical analysis of grazing-incidence, fast atom diffraction (GIFAD) allows us to develop simple analytic results that connect observed phenomena directly to basic aspects of the potential, such as the lateral variation of the well-dep…
View article: Microscopic origin of diffusive dynamics in the context of transition path time distributions for protein folding and unfolding
Microscopic origin of diffusive dynamics in the context of transition path time distributions for protein folding and unfolding Open
Experimentally measured transition path time distributions should be analyzed theoretically in terms of a master equation with nearest neighbor jumps between microstates instead of a diffusion equation of motion over a free energy barrier.
View article: The Influence of the Symmetry of Identical Particles on Flight Times
The Influence of the Symmetry of Identical Particles on Flight Times Open
In this work, our purpose is to show how the symmetry of identical particles can influence the time evolution of free particles in the nonrelativistic and relativistic domains as well as in the scattering by a potential δ-barrier. For this…
View article: Lower Bounds for Nonrelativistic Atomic Energies
Lower Bounds for Nonrelativistic Atomic Energies Open
A recently developed lower bound theory for Coulombic problems (E. Pollak, R. Martinazzo, J. Chem. Theory Comput. 2021, 17, 1535) is further developed and applied to the highly accurate calculation of the ground-state energy of two- (He, L…
View article: Comparison of a direct measure of barrier crossing times with indirect measures such as the Larmor time
Comparison of a direct measure of barrier crossing times with indirect measures such as the Larmor time Open
Different approaches for considering barrier crossing times are analyzed, with special emphasis on recent experiments which attempt to measure what is commonly referred to as the Larmor tunneling time. We show that that these experiments c…
View article: Comparison of an Improved Self-consistent Lower Bound Theory with Lehmann’s Method for Low-lying Eigenvalues
Comparison of an Improved Self-consistent Lower Bound Theory with Lehmann’s Method for Low-lying Eigenvalues Open
Ritz eigenvalues only provide upper bounds for the energy levels, while obtaining lower bounds requires at least the calculation of the variances associated with these eigenvalues. The well-known Weinstein and Temple lower bounds based on …