Symmetry-adapted perturbation theory with Kohn-Sham orbitals using non-empirically tuned, long-range-corrected...

Area of Science:

• Computational chemistry
• Quantum chemistry
• Theoretical chemistry

Background:

• Second-order symmetry-adapted perturbation theory (SAPT) is a method for calculating intermolecular interactions.
• Previous studies of SAPT using Kohn-Sham (KS) orbitals (SAPT(KS)) have limitations.
• Long-range corrected (LRC) functionals offer improved description of asymptotic behavior in density functional theory.

Purpose of the Study:

• To evaluate the performance of SAPT(KS) calculations employing non-empirically tuned LRC functionals.
• To assess the importance of the asymptotic limit condition for accurate energy component prediction.
• To investigate the accuracy of SAPT(KS) for various intermolecular interaction benchmarks.

Main Methods:

• Utilized non-empirically tuned LRC functionals for monomers in SAPT(KS) calculations.
• Tuned the range separation parameter to satisfy the condition: highest occupied KS energy = -ionization energy.
• Tested the methodology on He2, Ne2, and the S22 and S66 interaction energy datasets.

Main Results:

• Tuned LRC functionals are crucial for accurate prediction of non-dispersion energy components in SAPT(KS).
• SAPT(KS) still exhibits significant errors in dispersion energy calculations.
• Combining SAPT(KS) with an empirical dispersion potential yields accurate results for S22, S66, and the benzene dimer potential energy curve.

Conclusions:

• Tuned LRC functionals are a viable alternative to other asymptotic corrections in density-functional-based SAPT.
• The SAPT(KS) method, augmented with empirical dispersion, provides reliable predictions for intermolecular interactions.
• Recommendations are made for using tuned LRC functionals in coupled-perturbed SAPT(DFT) and dispersion-corrected SAPT(KS) calculations.