Quantum molecular dynamics simulations of liquid benzene using orbital optimization

The structure of liquid benzene is investigated by quantum molecular dynamics simulations. Results using variationally optimized numerical pseudo-atomic orbitals are compared to those of generic optimized orbitals. The accuracy of the first-principle calculations is compared with recent experimental findings. Simulations using minimal basis sets with optimized orbitals are shown to successfully predict the local structure of liquid benzene, while simulations with non-optimized minimal basis sets have significant errors in the structure of the first solvation shell. The use of a minimal optimized basis set considerably speeds up simulations, while preserving much of the accuracy of a larger basis set formed by generic orbitals. The transferability of the optimized orbitals is also explored under different environmental conditions.