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A fixed-node diffusion Monte Carlo study of the 1,2,3-tridehydrobenzene triradical
Lucas Koziol1, Miguel M Morales1
1Physical and Life Sciences Division, Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA.
The Journal of Chemical Physics
|June 16, 2014
Summary
Quantum Monte Carlo methods reveal the electronic structure of 1,2,3-tridehydrobenzene. Diffusion Monte Carlo (DMC) calculations confirm a nearly degenerate ground state, strengthening the assignment of a (2)A1 state.
Area of Science:
- Computational chemistry
- Quantum mechanics
- Theoretical chemistry
Background:
- 1,2,3-tridehydrobenzene is a reactive intermediate.
- Previous coupled cluster calculations suggested two nearly degenerate electronic states.
Purpose of the Study:
- To investigate the electronic structure of 1,2,3-tridehydrobenzene.
- To verify the near degeneracy of its low-lying electronic states.
- To confirm the ground state assignment.
Main Methods:
- Diffusion Monte Carlo (DMC) calculations.
- Multi-Reference Configuration Interaction (MRCI) trial wavefunctions.
- Complete Active Space (CAS) with 9 electrons in 9 orbitals (CAS(9,9)).
Main Results:
- DMC calculations achieved close agreement with high-level coupled-cluster results.
- The study confirmed the presence of two nearly degenerate electronic states.
- The assignment of a (2)A1 ground state was further strengthened.
Conclusions:
- Quantum Monte Carlo methods provide accurate electronic structure data for reactive intermediates.
- The (2)A1 state is confirmed as the ground state of 1,2,3-tridehydrobenzene.
- The computational approach validates previous findings and enhances understanding of this radical.
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