Potential energy surfaces for ring-rearrangement processes in tricarbonyl(cyclooctatetraene)chromium(0)

1991 ◽  
Vol 113 (20) ◽  
pp. 7513-7521 ◽  
Author(s):  
Michael S. Lawless ◽  
Dennis S. Marynick
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Energy Surfaces ◽  
Rearrangement Processes

A comparative study of the energetics, structures, and mechanisms of the HCN ↔ HNC and LiCN ↔ LiNC isomerizations

1996 ◽  
Vol 74 (6) ◽  
pp. 1072-1077 ◽  
Author(s):  
V. Sreedhara Rao ◽  
Amrendra Vijay ◽  
A.K. Chandra
Keyword(s):  
Potential Energy ◽  
Electron Correlation ◽  
Potential Energy Surfaces ◽  
Basis Sets ◽  
Ab Initio Theory ◽  
Molecular Bond ◽  
Bond Rearrangement ◽  
Energy Surfaces ◽  
Isomerization Processes ◽  
Rearrangement Processes

The potential energy surfaces of the HCN ↔ HNC and LiCN ↔ LiNC isomerization processes were determined by ab initio theory using fully optimized triple-zeta double polarization types of basis sets. Both the MP2 corrections and the QCISD level of calculations were performed to correct for the electron correlation. Results show that electron correlation has a considerable influence on the energetics and structures. Analysis of the intramolecular bond rearrangement processes reveals that, in both cases, H (or Li+) migrates in an almost elliptic path in the plane of the molecule. In HCN ↔ HNC, the migrating hydrogen interacts with the in-plane π,π* orbitals of CN, leading to a decrease in the C—N bond order. In LiCN ↔ LiNC, Li+ does not interact with the corresponding π,π* orbitals of CN. Key words: potential energy surfaces, intra-molecular bond rearrangement, bond orders, elliptic path, migration of Li+.

Resolving the Quadruple Bonding Conundrum in C2 Using Insights Derived from Excited State Potential Energy Surfaces: A Molecular Orbital Perspective

2019 ◽  
Author(s):  
Ishita Bhattacharjee ◽  
Debashree Ghosh ◽  
Ankan Paul
Keyword(s):  
Excited State ◽  
Potential Energy ◽  
Molecular Orbital ◽  
High Spin ◽  
Potential Energy Surfaces ◽  
Valence Bond ◽  
Deep Minimum ◽  
State Potential ◽  
Energy Surfaces ◽  
Mo Theory

The question of quadruple bonding in C<sub>2</sub> has emerged as a hot button issue, with opinions sharply divided between the practitioners of Valence Bond (VB) and Molecular Orbital (MO) theory. Here, we have systematically studied the Potential Energy Curves (PECs) of low lying high spin sigma states of C<sub>2</sub>, N<sub>2</sub> and Be<sub>2</sub> and HC≡CH using several MO based techniques such as CASSCF, RASSCF and MRCI. The analyses of the PECs for the<sup> 2S+1</sup>Σ<sub>g/u</sub> (with 2S+1=1,3,5,7,9) states of C<sub>2</sub> and comparisons with those of relevant dimers and the respective wavefunctions were conducted. We contend that unlike in the case of N<sub>2</sub> and HC≡CH, the presence of a deep minimum in the <sup>7</sup>Σ state of C<sub>2</sub> and CN<sup>+</sup> suggest a latent quadruple bonding nature in these two dimers. Hence, we have struck a reconciliatory note between the MO and VB approaches. The evidence provided by us can be experimentally verified, thus providing the window so that the narrative can move beyond theoretical conjectures.

Sign in / Sign up

Export Citation Format

Share Document