Pseudopotential‐fragment spectroscopy for organic molecules and carbon allotropes

Abstract

Following on from a previous work (Punter et al., IJQC 2019, 119, 23), pseudopotential sets are developed and tested for a variety of sp 2 and sp 3 carbon fragments. These fragments contain only one or two explicit protons and electrons, and make use of non-atom-centered potentials. They are tested with density functional theory calculations in a selection of chemical environments in which several physical characteristics, including orbital and first ionization energies, are found to be well reproduced.They are then employed in the reproduction of molecular absorption spectra for large organic molecules and carbon allotropes, and are found to recreate both absorption and electronic circular dichroism spectra to a high accuracy. They are also found significantly to increase the computational efficiency of time dependent density functional theory (TDDFT) calculations in which they are used. K E Y W O R D S electronic circular dichroism, electronic structure, hybridized carbon, pseudopotentials, spectroscopy |fflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflffl{zfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflfflffl} atom-centred potentialswith Y 0, 0 the s spherical harmonic, Y 1, m the p spherical harmonics (across all m), and r 0 J the relative fixed position of the Jth potential with respect to the origin of the pseudoatom to which the potentials are assigned.