1 research outputs found
TDDFT Assessment of Functionals for Optical 0–0 Transitions in Small Radicals
Using
LR-TDDFT, we calculated the 0–0 energies of 15 small
radicals for which the experimental values in gas phase are available.
We used 17 functionals. It turned out that B3LYP, M06-2X, ωB97X-D,
CAM-B3LYP, and HSE06 functionals are the most effective functionals
in terms of root-mean-square and average unsigned deviation. Using
the standard value (0.47 <i>a</i><sub>0</sub><sup>–1</sup>) of the attenuation parameter
ω, the long-range-corrected LC-GGA functionals give poor results.
However, the LC-PBE with ω = 0.25 <i>a</i><sub>0</sub><sup>–1</sup> give a
performance similar to that of B3LYP. Taking into account zero-point
correction improves the results, but the contribution of adiabatic
correction is more important than that due to the vibration. The vertical
approximation is certainly not recommended. An adiabatic calculation
seems to give a good compromise between computing time (and resources)
and reliability of the results for most of molecules investigated
in this work