Pseudopotentials for hybridized carbon atoms

Abstract

Pseudopotentials for hybridized atoms are extracted and combined. The study focuses on sp(2) carbon atoms and their combination to give rise to a π electronic system. As electrons of interest are treated explicitly, any ab initio method can be used, thus, configuration interaction methods and time-dependent density functional theory are used and compared. All electron and pseudopotential calculations are in good agreement for electronic transition spectroscopy (0.2 eV difference), geometrical parameters (error of 0.8 pm), and reaction energies.

Atomic pseudopotentials for reproducing π‐orbital electron behavior in sp2 carbon atoms

“…More interestingly, a very good agreement between reference and pseudosystems is obtained for TD‐DFT calculations (for the π ‐ π * excitation), which suggests that the virtual space is of good quality. We also compare TD‐DFT results for this system and results of a previous work of some of the authors, which match to within 3% (see SI) . Let us recall here that in our previous work, potentials were placed at the center of bonds, meaning that the pseudopotentials generated, while effective, were time‐consuming to set up for each molecule.…”

“…In this section we propose a physical interpretation of our pseudopotentials. This provides a conceptual advantage with respect to our previous work, where the pseudopotentials were simply relying on a shifting of the orbitals to map the reference ones.…”

“…The correlation will then be determined by the choice of the method. As in our previous work, we take the planar as our starting system to be reproduced. It is the smallest system containing one and only one sp 2 ‐hybridized carbon atom.…”