Analyses of bifurcation of reaction pathways on a global reaction route map: A case study of gold cluster Au5

Abstract

Articles you may be interested inA global reaction route map is generated for Au 5 by the anharmonic downward distortion following method in which 5 minima and 14 transition states (TSs) are located. Through vibrational analyses in the 3N − 7 (N = 5) dimensional space orthogonal to the intrinsic reaction coordinate (IRC), along all the IRCs, four IRCs are found to have valley-ridge transition (VRT) points on the way where a potential curvature changes its sign from positive to negative in a direction orthogonal to the IRC. The detailed mechanisms of bifurcations related to the VRTs are discussed by surveying a landscape of the global reaction route map, and the connectivity of VRT points and minima is clarified. Branching of the products through bifurcations is confirmed by ab initio molecular dynamics simulations starting from the TSs. A new feature of the reaction pathways, unification, is found and discussed. C 2015 AIP Publishing LLC. [http://dx

Visualization of the Dynamics Effect: Projection of on-the-Fly Trajectories to the Subspace Spanned by the Static Reaction Path Network

“…As the second application, oCMDS is applied to the structural changes of Au5 cluster which was investigated previously by ADDF, 8 TOF-MD, 12 and CMDS approaches. 18 As shown in Fig.…”

“…[3][4][5] It is also known that an unstable ridge region sometimes appears on the IRC path through a valley-ridge inflection (or transition) point, which leads to the reaction path bifurcation in some cases. [6][7][8] Such dynamics effects can be examined by trajectory on-the-fly molecular dynamics (TOF-MD) approach [9][10][11] in which atomic positions and velocities are evolved by the Newton's equation of motion based on the atomic forces determined from quantum chemical calculations. On-the-fly trajectories explore the PES with a given energy, and the route is not restricted to the IRC paths; they can reach several different isomer structures or dissociative products.…”

Automated Search of Minimum Free‐Energy Path by Umbrella Integration

“…To control ADDF for MFEP bifurcations, we will modify our algorithm using the method proposed for global reaction route mapping on potential energy. [46,47] The SHS method for alanine dipeptide is demonstrated on potential energy surface; [48] the potential energy differences between C ax 7 and TS1 is 6.7 kcal/mol. In this study, the free energy differences between C ax 7 and TS1 is 5.45 kcal/mol; this value is derived from the temperature of the systems (0 or 298.15 K), the reaction coordinates (full coordinates or two dihedrals) and the level of calculations (ab initio or empirical force field).…”

Analyses of trajectory on-the-fly based on the global reaction route map

“…Through the present analyses, one can discuss dynamical aspect of the reaction routes based on the static reaction-path network. The analyses were applied to structural transformations of a small gold cluster, Au 5 , for which we reported detailed analyses of a global reaction route map, 18 including branching pathways caused by a valley-ridge transition (VRT) points on the IRC. 19,20…”

“…The analyses were applied to structural transformations of a small gold cluster, Au 5 , for which we reported detailed analyses of a global reaction route map, 18 including branching pathways caused by a valley-ridge transition (VRT) points on the IRC. 19,20…”