On the Nature of Bonding in the Photochemical Addition of Two Ethylenes: C-C Bond Formation in the Excited State?

<div><p>In this work, the 2s+2s (face-to-face) prototypical example of a photochemical reaction has been re-examined to characterize the evolution of chemical bonding. The analysis of the electron localization function (as an indirect measure of the Pauli principle) along the minimum energy path provides strong evidence in support that CC bond formation occurs not in the excited state but at the ground electronic state after crossing the rhombohedral S₁/S₀ conical intersection. </p></div><br>

On the Nature of Bonding in the Photochemical Addition of Two Ethylenes: C-C Bond Formation in the Excited State?

<div><p>In this work, the 2s+2s (face-to-face) prototypical example of a photochemical reaction has been re-examined to characterize the evolution of chemical bonding. The analysis of the electron localization function (as an indirect measure of the Pauli principle) along the minimum energy path provides strong evidence in support that CC bond formation occurs not in the excited state but at the ground electronic state after crossing the rhombohedral S₁/S₀ conical intersection. </p></div><br>

Combining Evolutionary Conservation and Quantum Topological Analyses to Determine QM Subsystems for Biomolecular QM/MM Simulations

We present an approach that combines protein sequence/structure evolution and electron localization function (ELF) analyses. The combination of these two analysis allows the determination of whether a residue needs to be included in the QM subsystem, or can be represented by the MM environment. We have applied this approach on two systems previously investigated by QM/MM simulations, 4{oxalocrotonate tautomerase (4OT), and ten-eleven translocation-2 (TET2), that provide examples where fragments may or may not need to be included in the QM subsystem. Subsequently, we present the use of this approach to determine the appropriate QM subsystem to calculate the minimum energy path (MEP) for the reaction catalyzed by human DNA polymerase lambda? with a third cation in the active site.

Combining Evolutionary Conservation and Quantum Topological Analyses to Determine QM Subsystems for Biomolecular QM/MM Simulations

We present an approach that combines protein sequence/structure evolution and electron localization function (ELF) analyses. The combination of these two analysis allows the determination of whether a residue needs to be included in the QM subsystem, or can be represented by the MM environment. We have applied this approach on two systems previously investigated by QM/MM simulations, 4{oxalocrotonate tautomerase (4OT), and ten-eleven translocation-2 (TET2), that provide examples where fragments may or may not need to be included in the QM subsystem. Subsequently, we present the use of this approach to determine the appropriate QM subsystem to calculate the minimum energy path (MEP) for the reaction catalyzed by human DNA polymerase lambda? with a third cation in the active site.

Combining Evolutionary Conservation and Quantum Topological Analyses to Determine QM Subsystems for Biomolecular QM/MM Simulations

We present an approach that combines protein sequence/structure evolution and electron localization function (ELF) analyses. The combination of these two analysis allows the determination of whether a residue needs to be included in the QM subsystem, or can be represented by the MM environment. We have applied this approach on two systems previously investigated by QM/MM simulations, 4{oxalocrotonate tautomerase (4OT), and ten-eleven translocation-2 (TET2), that provide examples where fragments may or may not need to be included in the QM subsystem. Subsequently, we present the use of this approach to determine the appropriate QM subsystem to calculate the minimum energy path (MEP) for the reaction catalyzed by human DNA polymerase lambda? with a third cation in the active site.

On apparent barrier-free reactions

Rate coefficients of bi-molecular chemical reactions are fundamental for kinetic models. The rate coefficient dependence on temperature is commonly extracted from the analyses of the reaction minimum energy path. However, a full dimension study of the same reaction may suggest a different asymptotic low-temperature limit in the rate constant than the obtained from the energetic profile.