Hirshfeld-I charges in linear combination of atomic orbitals periodic calculations

Abstract

Hirshfeld-I charges were implemented in the Crystal code, for periodic calculations with localized atomic basis sets. Some particular features of the present periodic implementation are detailed and discussed by means of selected illustrating examples. In these examples, the Hirshfeld-I charges are somewhere between the Bader and the Mulliken values and closer to the former. The implementation exploits heavily symmetry aspects and is shown to scale linearly with the unit cell dimension.Keywords Hirshfeld Iterative · Periodic calculations · Ab Initio · LCAO To A. Vela for his high human and scientific qualities.

First Principles Simulations on Migration Paths of Oxygen Interstitials in MgAl2O4

“…Both methods clearly show that Mg-O bond is fully ionic (zero bond population), while Al-O bond nature is mixed ionic-covalent. As it was shown for corundum, [23] Mulliken population analysis demonstrated an O-Al electron back-donation which is also observed in spinel.…”

“…for self‐consistency procedure. The effective charges on atoms were evaluated using two different methods: Mulliken population analysis and Hirshfeld‐I method as implemented into the CRYSTAL17 code, whereas the bond properties were made using TOPOND code . Direct frozen phonon method was used for vibrational frequency calculations .…”

Piezoelectric, elastic, Infrared and Raman behavior of ZnO wurtzite under pressure from periodic DFT calculations

“…The Hirshfeld-I method, which has renewed the interest in the original Hirshfeld scheme [43], eliminates the need of calculating the promolecular density by replacing them with spherical symmetric weight functions, optimized through an iterative procedure. Its extension to periodic systems has been recently implemented [44] in the development version of the CRYSTAL program.…”

Quantum‐mechanical condensed matter simulations with CRYSTAL

“…In previous versions of the Crystal program, Mulliken, Born, and Bader charges could be computed. In Crystal17 , the Hirshfeld‐I partitioning Scheme (HI‐I) (Bultinck, Alsenoy, Ayers, & Carbó‐Dorca, ), which presents some improvements with respect to the original Hirshfeld scheme (Hirshfeld, ), has also been implemented (Zicovich‐Wilson, Navarrete‐López, Ho, & Casassa, ). In particular, an algorithm to deal with open‐shell systems has been included, and the need to evaluate the promolecular density has been eliminated by implementing the Iterative Stockholder Atoms method (Lillestolen & Wheatley, ).…”

“…In particular, an algorithm to deal with open-shell systems has been included, and the need to evaluate the promolecular density has been eliminated by implementing the Iterative Stockholder Atoms method (Lillestolen & Wheatley, 2009). The implementation fully exploits the point-symmetry of the system and has been shown to scale linearly with the unit cell size (Zicovich-Wilson et al, 2009). In Table 3, atomic charges as obtained with the HI-I method are reported and compared with Mulliken, Born (computed through an analytical CPHF/KS approach ), and Bader charges (Bader, 1990) from the Quantum Theory of Atoms in Molecules (QTAIM). The latter is considered to be one of the most rigorous (but costly) partitioning schemes.…”