Analytic projection from plane-wave and PAW wavefunctions and application to chemical-bonding analysis in solids

Abstract

Quantum-chemical computations of solids benefit enormously from numerically efficient plane-wave (PW) basis sets, and together with the projector augmented-wave (PAW) method, the latter have risen to one of the predominant standards in computational solid-state sciences. Despite their advantages, plane waves lack local information, which makes the interpretation of local densities-of-states (DOS) difficult and precludes the direct use of atom-resolved chemical bonding indicators such as the crystal orbital overlap population (COOP) and the crystal orbital Hamilton population (COHP) techniques. Recently, a number of methods have been proposed to overcome this fundamental issue, built around the concept of basis-set projection onto a local auxiliary basis. In this work, we propose a novel computational technique toward this goal by transferring the PW/PAW wavefunctions to a properly chosen local basis using analytically derived expressions. In particular, we describe a general approach to project both PW and PAW eigenstates onto given custom orbitals, which we then exemplify at the hand of contracted multiple-ζ Slater-type orbitals. The validity of the method presented here is illustrated by applications to chemical textbook examples-diamond, gallium arsenide, the transition-metal titanium-as well as nanoscale allotropes of carbon: a nanotube and the C60 fullerene. Remarkably, the analytical approach not only recovers the total and projected electronic DOS with a high degree of confidence, but it also yields a realistic chemical-bonding picture in the framework of the projected COHP method.

Synthesis, Crystal Structure, and Chemical Bonding of Ba2SiP4

“…8 wt %) and an unidentified minor phase as impurities. The sample was further characterized by 29 Selected interatomic distances /pm and angles /°B…”

“…The 31 P spectrum reveals additional weak signals from the impurity phases. The NMR resonances have linewidths (fwhm) of ≈ 500 Hz for 31 P and ≈ 205 Hz for 29 Si, which makes the distinc-Z. Anorg.…”

“…The Topas package [24] was used for Rietveld refinement. 29 Si-and 31 P-specta were measured with a Bruker Avance-III 500 spectrometer with a magnetic field of 11.74 T under MAS conditions at a Larmor frequency of ν 0 ( 29 Si) = 99.38 MHz and ν 0 ( 31 P) = 202.48 MHz. A commercial zirconia rotor (4 mm) was used with a rotation frequency of 10 kHz.…”

“…[28] The PAW eigenstates were projected onto localized crystal orbitals using LOBSTER. [29] Further details of the crystal structure investigations may be obtained from the Fachinformationszentrum Karlsruhe, 76344 EggensteinLeopoldshafen, Germany (Fax: +49-7247-808-666; E-Mail: crysdata@fiz-karlsruhe.de, http://www.fiz-karlsruhe.de/request for deposited data.html) on quoting the depository number CSD-433493. …”

Synthesis of Ti3AuC2, Ti3Au2C2 and Ti3IrC2 by noble metal substitution reaction in Ti3SiC2 for high-temperature-stable Ohmic contacts to SiC

“…10,11 To determine the dynamical stability of the studied ordered structure, we performed phonon calculations using the small displacement method, supercell sizes of at least 3x3x1 unit cells, along with the code Phonopy 12 . Density of states (DOS) and chemical bonding were investigated in terms of projected crystal orbital Hamiltonian populations (pCOHP) which were derived using the LOBSTER program 9,12,13 . Using this method the calculated band-structure energy is reconstructed into orbital interactions.…”