Complete optimisation of multi-configuration Jastrow wave functions by variational transcorrelated method.

Area of Science:

• Computational chemistry
• Quantum chemistry
• Electronic structure theory

Background:

• Accurate electronic structure calculations are crucial for understanding molecular properties.
• Optimizing multi-configuration wave functions, like the Jastrow wave function, is computationally demanding.
• Existing methods may struggle with the complexity of highly correlated systems.

Purpose of the Study:

• To evaluate the performance of the novel variational transcorrelated (VTC) method.
• To assess the VTC method's capability in optimizing multi-configuration Jastrow wave functions.
• To compare VTC results with established computational methods.

Main Methods:

• Implementation of the variational transcorrelated (VTC) method.
• Iterative optimization of orbitals using unitary transformations and Newton-Raphson schemes.
• Inclusion of third-order density matrices to handle three-body VTC potentials.
• Application to the C(2) molecule across various active spaces.

Main Results:

• The VTC method successfully optimizes the multi-configuration Jastrow wave function.
• Test calculations on the C(2) molecule yielded results comparable to variational quantum Monte Carlo.
• The VTC method demonstrated its ability to recover results from highly non-linear variational calculations.

Conclusions:

• The variational transcorrelated (VTC) method is a viable and effective approach for optimizing complex wave functions.
• VTC offers a practical way to achieve high accuracy in electronic structure calculations.
• This method shows promise for future applications in quantum chemistry.