Density functional calculations on first-row transition metals

Abstract

The excitation energies and ionization potentials of the atoms in the first transition series are notoriously difficult to compute accurately. Errors in calculated excitation energies can range from 1-4 eV at the Hartree-Fock level, and errors as high as 1.5eV are encountered for ionization energies. In the current work we present and discuss the results of a systematic study of the first transition series using a spin-restricted Kohn-Sham density-functional method with the gradient-corrected functionals of Becke and Lee, Yang and Parr. Ionization energies are observed to be in good agreement with experiment, with a mean absolute error of approximately 0.15eV; these results are comparable to the most accurate calculations to date, the Quadratic Configuration Interaction (QCISD(T)) calculations of Raghavachari and Trucks. Excitation energies are calculated with a mean error of approximately 0.5eV, compared with ∼ 1eV for the local density approximation and 0.1eV for QCISD(T). These gradient-corrected functionals appear to offer an attractive compromise between accuracy and computational effort.

Investigation of pure and Co2+-doped ZnO quantum dot electronic structures using the density functional theory: choosing the right functional

“…The Los Alamos double-ζ pseudo-core potential (LANL2DZ) [28]- [31] and associated basis set was used for all the atoms with the Zn (4s, 3d), Co (3s, 3p, 4s, 3d), and O (1s, 2s, 2p) electrons treated explicitly. Although generated from the Hartree-Fock atomic calculations, this pseudopotential was shown to perform well for the DFT-based calculations of the first row transition metal complexes, actinides and lanthanides [32]- [35].…”

Mesoporous Silica Functionalized by Cyclam–Metal Groups: Spectroscopic Studies and Numerical Modeling

“…The BLYP exchange-correlation potential was used as equivalent to the gradient correction proposed by Becke for the exchange part of potential [35] and for the Lee-Yang-Parr correlation correction [36][37][38]. All atoms were described within the triplef (TZ) basis set defined in the program database.…”

Density functional study of Ni bulk, surfaces and the adsorbate systems Ni(111)R30°–Cl, and Ni(111)(2×2)–K

“…This difficulty in obtaining the correct energy splitting between d n−1 s 1 and d n−2 s 2 was also identified as a general problem for the transition metals 32 , with the LDA, where a bias towards d n−1 s 1 of ∼ 1 eV was found. With a different gradient corrected functional (B-LYP), an energy splitting of -0.82 eV was computed 33 . There is, however, no reason why other properties should be affected by this problem.…”