Rotational g Tensors Calculated Using Hybrid Exchange-Correlation Functionals with the Optimized Effective Potential...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Accurate calculation of rotational g tensors is crucial for understanding molecular properties.
• Density Functional Theory (DFT) is a widely used method for electronic structure calculations.
• Hybrid exchange-correlation functionals offer improved accuracy but can be computationally intensive.

Purpose of the Study:

• To evaluate the accuracy of rotational g tensor calculations using DFT with hybrid functionals.
• To compare different computational approaches, including coupled and uncoupled methods.
• To investigate the impact of the optimized effective potential (OEP) on g tensor calculations.

Main Methods:

• Calculated 143 rotational g tensor elements for 58 molecules using three standard hybrid functionals.
• Employed an uncoupled approach with orbitals and eigenvalues from the multiplicative optimized effective potential (OEP).
• Compared results with conventional coupled approaches and generalized gradient approximation (GGA) functionals.

Main Results:

• The uncoupled OEP approach significantly improved rotational g tensor calculations.
• Mean absolute errors were reduced by a factor of 2 compared to experimental data.
• Mean errors and standard deviations decreased by over a factor of 3.

Conclusions:

• The uncoupled OEP-based hybrid DFT method provides a substantial improvement for rotational g tensor calculations.
• This approach outperforms conventional coupled methods and GGA functionals.
• More computationally expensive coupled-cluster approaches did not yield notable improvements over OEP-based DFT.