Relativistic effects on the Fukui function

Abstract

The extent of relativistic effects on the Fukui function, which describes local reactivity trends within conceptual density functional theory (DFT), and frontier orbital densities has been analysed on the basis of three benchmark molecules containing the heavy elements: Au, Pb, and Bi. Various approximate relativistic approaches have been tested and compared with the four-component fully relativistic reference. Scalar relativistic effects, as described by the scalar zeroth-order regular approximation methodology and effective core potential calculations, already provide a large part of the relativistic corrections. Inclusion of spin-orbit coupling effects improves the results, especially for the heavy p-block compounds. We thus expect that future conceptual DFT-based reactivity studies on heavy-element molecules can rely on one of the approximate relativistic methodologies.

Relativistic effects on x-ray structure factors

“…Finally, varying the level of approximation employed for the quantum chemical calculations allows for a systematic study of effects such as electron correlation [9][10][11][12][13][14][15], basis set size [6,16] or the type of model Hamiltonian on the resulting structure factors and electron densities. [9,[17][18][19][20][21][22][23] The aim of the present study is a systematic investigation of relativistic effects on X-ray structure factors. While this topic has been studied for atomic form factors f (r * ) in the past, [24][25][26][27] there exists up to date no thorough study in this respect on structure factors F(r * ) based on a fully-relativistic reference.…”

Negativity of Fukui function of some isolated s and p block elements: The role of orbital relaxation effect

“…It is known that negative values of the condensed-to-atom Fukui function is well correlated with the orbital relaxation effect and nodal surfaces of the frontier orbitals [12,13,15]. Recently, Bhattacharjee and Roy [16] elaborated that the values of [17], the calculations are computationally intensive and the analysis is not straightforward. A comparatively economic and affordable approach, within a non-relativistic framework, which includes relativistic effects, is by replacement of the inner atomic shells by effective core potential (ECP) [18,19].…”

Theoretical study of the local reactivity of electrophiles of the type MPR 3 + (M = Cu, Ag, Au ;R = −H, -Me, -Ph)

“…An analysis of local electrophilicity (ω k + ) provides the information of a particular atomic site in a molecule being attacked by a nucleophile. This local property has been proposed as a better intermolecular reactivity index than the Fukui function itself for analyzing electrophile-nucleophile interactions becuase the Fukui function allows to compare the sites selectivity within a molecule, while for a comparison of the reactivity of a specific site on different molecules, it is more appropriate to use a property that includes intrinsic information of the systems studied [19][20][21][22]. In this context, the local softness and the local electrophilicity descriptors are suitable to explain hard-soft and electrophile-nucleophile interactions, respectively.…”

“…This contribution focuses on the structure and properties of the MPR 3 + fragments by reactivity indices as introduced through conceptual density functional theory (CDFT) [19][20][21][22].…”