Orbital-Optimized Density Functional Calculations Improve Dipole Moment Predictions for Rydberg States
Researchers used orbital-optimized density functional theory with plane wave basis sets to calculate dipole moments of Rydberg excited states in molecules, finding this approach superior to time-dependent density functional theory. The study reveals that commonly used atomic basis sets produce inaccurate dipole moments for Rydberg states even when excitation energies are well-described. The findings have implications for accurately modeling highly diffuse excited states in quantum chemistry calculations.
A new computational study demonstrates that orbital-optimized density functional calculations with plane wave basis sets provide improved descriptions of dipole moments for Rydberg excited states, which are notoriously difficult to model due to their diffuse character. The researchers benchmarked several functionals (PBE, PBE0, and PBE with self-interaction correction) and found that standard single-augmented atomic basis sets fail to accurately predict dipole moments even when excitation energies are correctly reproduced. Plane wave representations offer more flexibility for capturing the diffuse nature of Rydberg orbitals, and the study shows that adding extra augmented diffuse functions to atomic basis sets provides only partial improvement. The generalized gradient approximation functional PBE performs reasonably well, while the hybrid functional PBE0 yields better results, though the self-interaction corrected variant produces larger errors despite correctly restoring asymptotic potential behavior.
What's missing
The study does not discuss computational cost comparisons between plane wave and atomic basis set approaches, nor does it address potential applications or implications for experimental spectroscopy or molecular property predictions.
What different sources said
- arXiv physicsCenter
Excited-state Properties Beyond the Excitation Energy from Orbital-Optimized Density Functional Calculations I: Dipole Moments of Rydberg States
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