Can ΔSCF and ROKS DFT-Based Methods Predict the Inversion of the Singlet–Triplet Gap in Organic Molecules? DOI
Danillo Valverde, Gaetano Ricci, J. C. Sancho‐García

et al.

Journal of Chemical Theory and Computation, Journal Year: 2025, Volume and Issue: unknown

Published: March 1, 2025

Inverted singlet–triplet gap systems (INVEST) have emerged as an intriguing class of materials with potential applications emitters in Organic Light Emitting Diodes (OLEDs). Indeed, this type material exhibits a negative energy (ΔEST), i.e., inversion the lowest singlet (S1) and triplet (T1) excited states, that goes against Hund's rule. In study, ΔEST set 15 INVEST molecules has been computed within framework Restricted Open-Shell Kohn–Sham (ROKS) Delta Self-Consistent Field (ΔSCF) methods results were benchmarked wavefunction-based calculations performed at EOM-CCSD, NEVPT2, SCS-CC2 levels. We find ROKS always (and wrongly) predicts positive global hybrid, meta-GGA, long-range corrected functionals is almost functional-independent. also show only way to obtain inverted was resort double hybrid functionals. contrast, using above-mentioned functionals, ΔSCF usually gives ΔEST, although are largely functional-dependent. Overall, applying method based on PBE0 functional provides MSD MAD respect EOM-CCSD results. further driven by different degrees orbital relaxation versus state well captured calculations. As matter fact, somehow mimics involvement higher-order excitations which leads difference spatial localization α β spins, thus introduces (local) spin polarization effects sourcing ΔEST. However, care should be taken when screen behavior view their limited quantitative correlation reference molecular data basis used here.

Language: Английский

Can ΔSCF and ROKS DFT-Based Methods Predict the Inversion of the Singlet–Triplet Gap in Organic Molecules? DOI
Danillo Valverde, Gaetano Ricci, J. C. Sancho‐García

et al.

Journal of Chemical Theory and Computation, Journal Year: 2025, Volume and Issue: unknown

Published: March 1, 2025

Inverted singlet–triplet gap systems (INVEST) have emerged as an intriguing class of materials with potential applications emitters in Organic Light Emitting Diodes (OLEDs). Indeed, this type material exhibits a negative energy (ΔEST), i.e., inversion the lowest singlet (S1) and triplet (T1) excited states, that goes against Hund's rule. In study, ΔEST set 15 INVEST molecules has been computed within framework Restricted Open-Shell Kohn–Sham (ROKS) Delta Self-Consistent Field (ΔSCF) methods results were benchmarked wavefunction-based calculations performed at EOM-CCSD, NEVPT2, SCS-CC2 levels. We find ROKS always (and wrongly) predicts positive global hybrid, meta-GGA, long-range corrected functionals is almost functional-independent. also show only way to obtain inverted was resort double hybrid functionals. contrast, using above-mentioned functionals, ΔSCF usually gives ΔEST, although are largely functional-dependent. Overall, applying method based on PBE0 functional provides MSD MAD respect EOM-CCSD results. further driven by different degrees orbital relaxation versus state well captured calculations. As matter fact, somehow mimics involvement higher-order excitations which leads difference spatial localization α β spins, thus introduces (local) spin polarization effects sourcing ΔEST. However, care should be taken when screen behavior view their limited quantitative correlation reference molecular data basis used here.

Language: Английский

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