All Outputs (11)

Quantum Tunneling Rates of Gas-Phase Reactions from On-the-Fly Instanton Calculations (2016)
Journal Article
Beyer, A. N., Richardson, J. O., Knowles, P. J., Rommel, J., & Althorpe, S. C. (2016). Quantum Tunneling Rates of Gas-Phase Reactions from On-the-Fly Instanton Calculations. Journal of Physical Chemistry Letters, 7(21), 4374-4379. https://doi.org/10.1021/acs.jpclett.6b02115

The instanton method obtains approximate tunneling rates from the minimum-action path (known as the instanton) linking reactants to the products at a given temperature. An efficient way to find the instanton is to search for saddle-points on the ring... Read More about Quantum Tunneling Rates of Gas-Phase Reactions from On-the-Fly Instanton Calculations.

Microcanonical and thermal instanton rate theory for chemical reactions at all temperatures (2016)
Journal Article
Richardson, J. O. (2016). Microcanonical and thermal instanton rate theory for chemical reactions at all temperatures. Faraday Discussions, 195, 49-67. https://doi.org/10.1039/c6fd00119j

Semiclassical instanton theory is used to study the quantum effects of tunnelling and delocalization in molecular systems. An analysis of the approximations involved in the method is presented based on a recent first-principles derivation of instanto... Read More about Microcanonical and thermal instanton rate theory for chemical reactions at all temperatures.

Concerted hydrogen-bond breaking by quantum tunneling in the water hexamer prism (2016)
Journal Article
Richardson, J. O., Pérez, C., Lobsiger, S., Reid, A. A., Temelso, B., Shields, G. C., …Althorpe, S. C. (2016). Concerted hydrogen-bond breaking by quantum tunneling in the water hexamer prism. Science, 351(6279), 1310-1313. https://doi.org/10.1126/science.aae0012

The nature of the intermolecular forces between water molecules is the same in small hydrogen-bonded clusters as in the bulk. The rotational spectra of the clusters therefore give insight into the intermolecular forces present in liquid water and ice... Read More about Concerted hydrogen-bond breaking by quantum tunneling in the water hexamer prism.

Derivation of instanton rate theory from first principles (2016)
Journal Article
Richardson, J. O. (2016). Derivation of instanton rate theory from first principles. The Journal of Chemical Physics, 144(11), Article 114106. https://doi.org/10.1063/1.4943866

Instanton rate theory is used to study tunneling events in a wide range of systems including low-temperature chemical reactions. Despite many successful applications, the method has never been obtained from first principles, relying instead on the “I... Read More about Derivation of instanton rate theory from first principles.

Ring-polymer instanton theory of electron transfer in the nonadiabatic limit (2015)
Journal Article
Richardson, J. O. (2015). Ring-polymer instanton theory of electron transfer in the nonadiabatic limit. The Journal of Chemical Physics, 143(13), Article 134116. https://doi.org/10.1063/1.4932362

We take the golden-rule instanton method derived in the previous paper [J. O. Richardson, R. Bauer, and M. Thoss, J. Chem. Phys. 143, 134115 (2015)] and reformulate it using a ring-polymer instanton approach. This gives equations which can be used to... Read More about Ring-polymer instanton theory of electron transfer in the nonadiabatic limit.

Semiclassical Green's functions and an instanton formulation of electron-transfer rates in the nonadiabatic limit (2015)
Journal Article
Richardson, J. O., Bauer, R., & Thoss, M. (2015). Semiclassical Green's functions and an instanton formulation of electron-transfer rates in the nonadiabatic limit. The Journal of Chemical Physics, 143(13), Article 134115. https://doi.org/10.1063/1.4932361

We present semiclassical approximations to Green’s functions of multidimensional systems, extending Gutzwiller’s work to the classically forbidden region. Based on steepest-descent integrals over these functions, we derive an instanton method for com... Read More about Semiclassical Green's functions and an instanton formulation of electron-transfer rates in the nonadiabatic limit.

Non-oscillatory flux correlation functions for efficient nonadiabatic rate theory (2014)
Journal Article
Richardson, J. O., & Thoss, M. (2014). Non-oscillatory flux correlation functions for efficient nonadiabatic rate theory. The Journal of Chemical Physics, 141(7), Article 074106. https://doi.org/10.1063/1.4892865

There is currently much interest in the development of improved trajectory-based methods for the simulation of nonadiabatic processes in complex systems. An important goal for such methods is the accurate calculation of the rate constant over a wide... Read More about Non-oscillatory flux correlation functions for efficient nonadiabatic rate theory.

Nonadiabatic ring-polymer molecular dynamics (2013)
Journal Article
Richardson, J. O., & Thoss, M. (2013). Nonadiabatic ring-polymer molecular dynamics. The Journal of Chemical Physics, 139(3), Article 031102. https://doi.org/10.1063/1.4816124

A new method based on an extension of ring-polymer molecular dynamics is proposed for the calculation of thermal correlation functions in electronically nonadiabatic systems. The ring-polymer dynamics are performed using a continuous-variable represe... Read More about Nonadiabatic ring-polymer molecular dynamics.

Instanton calculations of tunneling splittings for water dimer and trimer (2011)
Journal Article
Richardson, J. O., Althorpe, S. C., & Wales, D. J. (2011). Instanton calculations of tunneling splittings for water dimer and trimer. The Journal of Chemical Physics, 135(12), Article 124109. https://doi.org/10.1063/1.3640429

We investigate the ability of the recently developed ring-polymer instanton (RPI) method [J. O. Richardson and S. C. Althorpe, J. Chem. Phys. 134, 054109 (2011)] to treat tunneling in water clusters. We show that the RPI method is easy to extend to t... Read More about Instanton calculations of tunneling splittings for water dimer and trimer.

Ring-polymer instanton method for calculating tunneling splittings (2011)
Journal Article
Richardson, J. O., & Althorpe, S. C. (2011). Ring-polymer instanton method for calculating tunneling splittings. The Journal of Chemical Physics, 134(5), Article 054109. https://doi.org/10.1063/1.3530589

The semiclassical instanton expression for the tunneling splitting between two symmetric wells is rederived, starting from the ring-polymer representation of the quantum partition function. This leads to simpler mathematics by replacing functional de... Read More about Ring-polymer instanton method for calculating tunneling splittings.

Ring-polymer molecular dynamics rate-theory in the deep-tunneling regime: Connection with semiclassical instanton theory (2009)
Journal Article
Richardson, J. O., & Althorpe, S. C. (2009). Ring-polymer molecular dynamics rate-theory in the deep-tunneling regime: Connection with semiclassical instanton theory. The Journal of Chemical Physics, 131(21), Article 214106. https://doi.org/10.1063/1.3267318

We demonstrate that the ring-polymer molecular dynamics (RPMD) method is equivalent to an automated and approximate implementation of the “Im F” version of semiclassical instanton theory when used to calculate reaction rates in the deep-tunneling reg... Read More about Ring-polymer molecular dynamics rate-theory in the deep-tunneling regime: Connection with semiclassical instanton theory.