Hokkaido University · Materials Science
Professor Tetsuya Taketsugu's research lab specializes in theoretical and computational quantum chemistry, focusing on reaction dynamics, potential energy surfaces, and reaction mechanisms in molecular systems. The lab investigates intrinsic reaction coordinates, dynamic reaction paths, and tunneling effects in hydrogen-transfer processes, particularly in water clusters such as dimers and trimers. Using high-level ab initio methods like MP2 and UHF with large basis sets, the group explores complex reaction pathways, including bifurcating mechanisms and valley–ridge inflection points, to understand the geometric and electronic factors governing chemical reactivity. Their work provides deep insights into the dynamics of proton transfer and structural rearrangements at the quantum level.
Figures are computed from collected data and may differ slightly.
We propose two methods that may be used to describe the dynamic reaction path (DRP) based on an intrinsic reaction coordinate (IRC) or minimum energy path, to examine how the actual dynamics proceeds relative to the IRC path. In the first of these, any point on the DRP is expressed in terms of the IRC and the distance from the IRC path. In the second method, any DRP point is expressed in terms of the IRC, the curvature coordinate, and the distance from a two-dimensional ‘‘reaction plane’’ determ
The global minimum and transition states for the acceptor-tunnelling, donor-acceptor interchange and bifurcation tunnelling rearrangements of the water dimer, and the single-flip, bifurcation and concerted proton transfer processes in the water trimer have been reinvestigated. Our analysis of the tunnelling splittings and spectroscopy is based on ab initio calculations at the computational level of second-order M⊘ller-Plesset (MP2) theory with basis sets of aug-cc-pVXZ quality (X = D, T, Q for t
The intrinsic reaction path (IRP) often becomes unstable relative to some nontotally symmetric direction orthogonal to the path through a valley–ridge inflection point. We investigate geometric characters of the potential energy surface around the valley–ridge inflection boundary, and propose some ideas to determine a bifurcating reaction path, or to give a two-dimensional potential energy surface which connects bifurcating point and product regions. As a demonstration, bifurcating reaction path
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