### 研究领域

Theoretical

Our research investigates how the quantum properties of atomic nuclei affect chemical reaction rates and mechanisms. We develop and apply a wide range of theories and computational techniques, from exact solutions of the Schrödinger equation for small systems, to approximate Feynman path- integral approaches for larger systems.
First-principles calculations of wave functions of chemical reactions
We were the first group to calculate a complete time-dependent wave function that visualizes the entire dynamics of a chemical reaction from approach of the reactants through to scattering of the products into space. This work is done in collaboration with a leading experimental group (R.N. Zare, Stanford) who measure detailed product-scattering patterns that our calculations reproduce and interpret in terms of first-principles quantum mechanics.
Instanton simulations of quantum tunnelling
Instantons arise when Feynman path-integral theory is used to describe quantum tunnelling through barriers; they describe the dominant tunnelling path, which gives an approximate but physically rigorous description of the tunnelling dynamics. We have recently developed and extended instanton theory such that the instantons are represented by a series of beads which can be rapidly strung together to describe quantum tunnelling in complex systems. We are currently applying this method to tunnelling in water clusters (in collaboration with Prof. D.J. Wales), and to proton transfer reactions in solution.
Winding effects at conical intersections
Conical intersections arise when potential energy surfaces intersect. We have found that the nuclear wave functions at such intersections can be unwound, such that contributions from Feynman paths that wind different numbers of times around the intersection can be rigorously separated. This gives rise to quantum interference effects; we are currently investigating how such effects influence the efficiency of relaxation through a conical intersection.

### 近期论文

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Is the simplest chemical reaction really so simple?
J Jankunas, M Sneha, R N Zare, F Bouakline, S C Althorpe, D Herráez-Aguilar, and F J Aoiz
PNAS 111, 15-20 (2014)
DOI: 10.1073/pnas.1315725111 PDF
Shallow-tunnelling correction factor for use with Wigner–Eyring transition-state theory
Y Zhang, J B Rommel, M T Cvitas and S C Althorpe
Phys. Chem. Chem. Phys. 16, 24292-24300 (2014)
DOI: 10.1039/c4cp03235g
Which Is Better at Predicting Quantum-Tunneling Rates: Quantum Transition-State Theory or Free-Energy Instanton Theory?
Y Zhang, T Stecher, M T Cvitas and S C Althorpe
J. Phys. Chem. Lett. 5, 3976−3980 (2014)
DOI: 10.1021/jz501889v PDF
On the uniqueness of t → 0+ quantum transition-state theory
T J H Hele and S C Althorpe
J. Chem. Phys. 139, 084116 (9 pages) (2013)
DOI: 10.1063/1.4819077 PDF
Derivation of a true (t → 0+) quantum transition-state theory. II. Recovery of the exact quantum rate in the absence of recrossing
S C Althorpe and T J H Hele
J. Chem. Phys. 139, 084115 (13 pages) (2013)
DOI: 10.1063/1.4819076 PDF
Hunt for geometric phase effects in H + HD → HD(v′, j′) + H
J Jankunas, M Sneha, R N Zare, F Bouakline, and S C Althorpe
J. Chem. Phys. 139, 144316 (6 pages) (2013)
DOI: 10.1063/1.4821601 PDF
Investigation of Terahertz Vibration-Rotation Tunneling Spectra for the Water Octamer
J O Richardson, D J Wales, S C Althorpe, R P McLaughlin, M R Viant, O Shih, and R J Saykally
J. Phys. Chem. A 117, 6960-6966 (2013)
DOI: 10.1021/jp311306a PDF
A Chebyshev method for state-to-state reactive scattering using reactant-product decoupling: OH + H2 → H2O + H
M T Cvitas and S C Althorpe
J. Chem. Phys. 139, 064307 (13 pages) (2013)
DOI: 10.1063/1.4817241 PDF
Derivation of a true (t → 0+) quantum transition-state theory. I. Uniqueness and equivalence to ring-polymer molecular dynamics transition-state theory
T J H Hele and S C Althorpe
J. Chem. Phys. 138, 084108 (13 pages) (2013)
DOI: 10.1063/1.4792697 PDF
Simultaneous measurement of reactive and inelastic scattering: Differential cross section of the H+HD→HD(v', j')+H reaction
J Jankunas, M Sneha, R N Zare, F Bouakline, and S C Althorpe
Z. Phys. Chem. 227, 1281-1300 (2013)
DOI: 10.1524/zpch.2013.0407 PDF
Disagreement between theory and experiment grows with increasing rotational excitation of HD(v', j') product for the H + D2 reaction
J Jankunas, M Sneha, R N Zare, F Bouakline and S C Althorpe
J. Chem. Phys. 138, 094310 (10 pages) (2013)
DOI: 10.1063/1.4793557 PDF
Seemingly Anomalous Angular Distributions in H + D2 Reactive Scattering
J Jankunas, R N Zare, F Bouakline, S C Althorpe, D Herráez-Aguilar and F J Aoiz
Science 336, 1687-1690 (2012)
DOI: 10.1126/science.1221329 PDF
A state-to-state dynamical study of the Br + H2 reaction: comparison of quantum and classical trajectory results
A N Panda, D Herráez-Aguilar, P G Jambrin, J Aldegunde, S C Althorpe and F J Aoiz
Phys. Chem. Chem. Phys. 14, 13067-13075 (2012)
DOI: 10.1039/C2CP41825H
Improved free-energy interpolation scheme for obtaining gas-phase reaction rates from ring-polymer molecular dynamics
T Stecher and S C Althorpe
Mol. Phys. 110, 875-883 (2012)
DOI: 10.1080/00268976.2012.666574 PDF
Instanton calculations of tunneling splittings for water dimer and trimer
J O Richardson, S C Althorpe and D J Wales
J. Chem. Phys. 135, 124109 (12 pgs) (2011)
DOI: 10.1063/1.3640429 PDF
Symmetry analysis of geometric-phase effects in quantum dynamics
S C Althorpe
Conical Intersections: Theory, Computation and Experiment (Advanced Series in Physical Chemistry) ed. W. Domcke, D.R. Yarkony and H. Köppel (World Scientific, Singapore, 2011)
On the equivalence of two commonly used forms of semiclassical instanton theory
S C Althorpe
J. Chem. Phys. 134, 114104 (8 pgs) (2011)
DOI: 10.1063/1.3563045
Ring-polymer instanton method for calculating tunneling splittings
J O Richardson and S C Althorpe
J. Chem. Phys. 134, 054109 (11 pgs) (2011)
DOI: 10.1063/1.3530589
State-to-state reactive scattering in 6 dimensions: OH + H2 → H2O + H (J=0)
M T Cvitas and S C Althorpe
J. Chem. Phys. 134, 024309 (21 pgs) (2011)
DOI: 10.1063/1.3525541
Differential cross sections for H + D2 → HD(v′ = 2, j′ = 0,3,6,9) + D at center-of-mass collision energies of 1.25, 1.61, and 1.97 eV
N C-M Bartlett, J Jankunas, T Goswami, R N Zare, F Bouakline and S C Althorpe
Phys. Chem. Chem. Phys. 13, 8175-8179 (2011)
DOI: 10.1039/C0CP02460K