Zimmermann, Tomas
Vanicek, Jiri
Three applications of path integrals: equilibrium and kinetic isotope effects, and the temperature dependence of the rate constant of the [1,5] sigmatropic hydrogen shift in (Z)-1,3-pentadiene
Journal of Molecular Modeling
Journal of Molecular Modeling
Journal of Molecular Modeling
Journal of Molecular Modeling
16
11
Anharmonicity effects
Equilibrium isotope effect
Kinetic isotope effect
Path integral
Quantum instanton
Rotational-vibrational coupling
[1,5] Sigmatropic hydrogen shift
Temperature dependence of the rate constant
Tunneling
2010
2010
Recent experiments have confirmed the importance of nuclear quantum effects even in large biomolecules at physiological temperature. Here we describe how the path integral formalism can be used to describe rigorously the nuclear quantum effects on equilibrium and kinetic properties of molecules. Specifically, we explain how path integrals can be employed to evaluate the equilibrium (EIE) and kinetic (KIE) isotope effects, and the temperature dependence of the rate constant. The methodology is applied to the [1,5] sigmatropic hydrogen shift in pentadiene. Both the KIE and the temperature dependence of the rate constant confirm the importance of tunneling and other nuclear quantum effects as well as of the anharmonicity of the potential energy surface. Moreover, previous results on the KIE were improved by using a combination of a high level electronic structure calculation within the harmonic approximation with a path integral anharmonicity correction using a lower level method.
Springer Verlag
1610-2940
Journal of Molecular Modeling
Journal Articles
10.1007/s00894-010-0711-y