Quantum Tunneling Effects, Solving the Schrodinger Equation Bottleneck Recognized as Best Papers by The Journal of Chemical Physics

MELVILLE, N.Y., May 6, 2020 /PRNewswire/ -- Two early career researchers have been announced as the winners of the inaugural Best Paper by an Emerging Investigator Award by The Journal of Chemical Physics (JCP), a publication of AIP Publishing.

Original research from Jeremy O. Richardson and Sandeep Sharma was selected by a selection committee composed of Editorial Advisory Board members from the pool of papers included in the highly selective 2019 JCP Emerging Investigators Special Collection. Richardson and Sharma were awarded $2,000 each and invited to write a Perspective article on their field for publication by The Journal of Chemical Physics.

Qualifying submissions have a principal investigator within 10 years of their graduate degree graduation date and encompass the entire scope of the journal. Submissions are currently open for the 2020 JCP Emerging Investigators Special Collection.

Jeremy O. Richardson

Jeremy O. Richardson was born in Cardiff, Wales, and holds a doctorate in chemistry from the University of Cambridge in the United Kingdom.

Throughout most of his scientific career, Richardson's research focus has been on studying molecular systems at the intersection of the classical and quantum limits. Molecules behave according to the laws of quantum mechanics, but these laws are difficult to model in computational algorithms. One way to overcome this is to ignore the quantum effects and simply simulate molecules using classical mechanics. Though efficient, this method introduces additional errors in calculations.

"My research attempts to find a compromise between these two alternatives, which we call semiclassical because they are halfway between classical and quantum in both accuracy and efficiency," said Richardson.

In the winning paper, "Instanton formulation of Fermi's golden rule in the Marcus inverted regime," which was published in The Journal of Chemical Physics on Jan. 17, 2020, Richardson and his graduate student Eric R. Heller extended the semiclassical instanton theory to calculate quantum tunneling effects in electron-transfer reactions in the Marcus inverted regime. Though tunneling is known to be an important quantum effect that allows for reactions that are energetically prohibited classically, it had been previously ignored within Marcus theory, which explains electron transfer reaction rates. A reconciliation between the two was thought to be impossible in this regime.

"This manuscript sheds interesting new light on the quantum mechanics of electron transfer in the Marcus inverted regime, where tunneling through the reaction barrier can enhance the rate of an electron transfer reaction by orders of magnitude," according to a JCP editor.

Though the paper currently serves as a proof-of-concept, the researchers plan to use their method to study to more complicated systems.

"Eric and I are delighted to have received this recognition of our work and hope that interested readers will suggest exciting applications for our new method," Richardson said.

Sandeep Sharma

Sandeep Sharma was born in Mumbai, India, and received his doctorate in chemical engineering from the Massachusetts Institute of Technology. He focused on understanding the combustion and formation processes of polycyclic aromatic hydrocarbons, the precursors to soot. Since then, his primary attention has shifted toward developing methods for calculating electronic structure theory of correlated systems.

In his winning paper, "Multireference configuration interaction and perturbation theory without reduced density matrices," which was published in The Journal of Chemical Physics on Dec. 2, 2019, Sharma and his collaborators overcame the bottleneck of prohibitively expensive calculation and memory requirements for solving the Schrödinger equation for large, complex systems of transition metal atoms. Because it is impossible to determine exact solutions for such arbitrarily complex systems, the best-case scenario is to develop a heuristic approach, consisting of a family of algorithms, each of which works on a subset of the larger system.

"The accurate calculation of electronic structure is very difficult in large, strongly correlated systems.  To treat such situations, a suite of so-called 'multireference' techniques have been developed, but these approaches are costly and difficult to use for large systems," said a JCP editor. "The authors devise a stochastic means to circumvent a major bottleneck in two paradigmatic types of these established approaches, paving the way for a more facile accurate treatment of large-scale strongly correlated problems."

The work demonstrates that a class of methods previously limited to smaller molecules can be extended into more complicated systems, serving as a step toward the best-case scenario. By manipulating the equations in just the right way, the researchers transformed a single, expensive step into a series of tiny, cheap calculations.

"I am very pleased to receive this award," he said. "I have read with great interest the papers that were published in this issue, some of which were written by colleagues and friends that I know and respect, so it was all the more gratifying when the editors of The Journal of Chemical Physics told me that my work was selected."

ABOUT THE JOURNAL

The Journal of Chemical Physics is an international journal that publishes cutting edge research in all areas of modern physical chemistry and chemical physics. See https://aip.scitation.org/journal/jcp

ABOUT THE AWARD

The Journal of Chemical Physics is committed to recognizing the excellent work of early career investigators. We are therefore proud to present the JCP Emerging Investigators Special Collection and the accompanying JCP Best Paper by an Emerging Investigator Awards. A subcommittee of the JCP Editorial Advisory Board, not journal editors, choose two winners from among the papers accepted to the special collection.

ABOUT AIP PUBLISHING

AIP Publishing is a wholly owned not-for-profit subsidiary of the American Institute of Physics (AIP). AIP Publishing's mission is to support the charitable, scientific and educational purposes of AIP through scholarly publishing activities in the fields of the physical and related sciences on its own behalf and on behalf of our publishing partners to help them proactively advance their missions.

SOURCE AIP Publishing

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