First principles optimally tuned range-separated density functional theory for prediction of phosphorus-hydrogen...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Spectroscopy

Background:

• Density Functional Theory (DFT) is crucial for electronic structure calculations.
• Developing accurate and non-empirical exchange-correlation functionals is an ongoing challenge.
• Nuclear Magnetic Resonance (NMR) spectroscopy, particularly spin-spin coupling constants (SSCCs), provides valuable molecular structural information.

Purpose of the Study:

• To develop and benchmark Optimally Tuned Range-Separated (OT-RS) density functional theory (DFT) functionals for predicting phosphorus-hydrogen (P-H) spin-spin coupling constants (SSCCs).
• To investigate the influence of short- and long-range exchange interactions and range separation parameters on P-H SSCC calculations.
• To propose new non-empirical OT-RS functionals and assess their performance against existing methods.

Main Methods:

• Development and application of two novel non-empirical OT-RS DFT functionals.
• Benchmarking against standard long-range corrected (LC) functionals and other DFT approximations.
• Analysis of the contributions of short- and long-range exchange interactions to SSCCs.
• Validation of functional performance for P-H SSCCs in both gas and continuum solvent phases.

Main Results:

• The proposed OT-RS functionals demonstrate improved accuracy in predicting experimental P-H SSCCs compared to conventional LC approximations.
• The new functionals often outperform other DFT functionals from various rungs of Jacob's Ladder.
• Analysis revealed the critical role of both short- and long-range exchange and range separation parameters in accurate SSCC calculations.
• The models were validated for predicting SSCCs and their components in continuum solvents.

Conclusions:

• Novel non-empirical OT-RS DFT functionals provide a highly accurate and computationally efficient method for predicting P-H SSCCs.
• This work highlights the potential of OT-RS DFT for systematic development of functionals tailored for NMR parameter prediction.
• The findings encourage further exploration of OT-RS DFT for modeling various NMR parameters.