Themed collection Developments in Density Functional Theory

This issue provides an overview of the state-of-the-art of DFT, ranging from mathematical and software developments, via topics in chemical bonding theory, to all kinds of molecular and material properties. Through this issue, we also celebrate the enormous contributions that Evert Jan Baerends has made to this field.

Scaling rules differ for early and late transition metals. Their electronic structure and topological bond analysis are shown.

We present an ab initio molecular dynamics approach to characterize proton-coupled electron transfer catalytic steps and identify the preferred reaction mechanism.

Molecules exposed to an electromagnetic field due to the presence of nearby nanoparticles are known to be affected.

The generalised coupled oscillator (GCO) mechanism implies that the stability of the computed VCD sign should be assigned by monitoring the uncertainties in the relative orientation of the GCO fragments and in the nuclear displacement vectors, i.e. not the magnitude of the dissymmetry factor.

This work reports the development of a generalised coupled oscillator expression for VCD that is exact within the harmonic approximation and is applicable to all types of normal modes, regardless whether the considered molecule is symmetric or asymmetric.

In dynamics studies of hydrogen dissociation on CO pre-covered Ru(0001) the simulation cell size is important for describing energy exchange.

The desolvation and size of monovalent alkali metal ions are of equal importance for the cation affinity of guanine quadruplexes.

Constrained Subsystem Density Fucntional Theory (CSDFT) allows to compute diabatic states for charge transfer reactions using the machinery of the constrained DFT method, and at the same time is able to embed such diabatic states in a molecular environment via a subsystem DFT scheme.

Multiwavelets are emerging as an attractive alternative to traditional basis sets such as Gaussian-type orbitals and plane waves.

We calculated the frequency dependent macroscopic dielectric function and second-harmonic generation of cubic ZnS, ZnSe and ZnTe within time-dependent density-polarisation functional theory.

The [Fe_a3, Cu_B] dinuclear center states along the O–O bond cleavage pathway in ba₃ cytochrome c oxidase have been studied using broken-symmetry density functional calculations.

A new derivation of semi-local calibration functions is proposed, to ameliorate the gauge problem of exchange-energy densities in local hybrid functionals.

Analytical excitation-energy gradients from frozen-density embedding–time-dependent density functional theory are derived and implemented, which are important for photochemistry in complex systems.

Probabilities of single ionization channels or double and multiple simultaneous ionization can be determined from exact master equations for time-dependent Dyson orbitals.

We present an unconditionally stable TDDFT inversion algorithm based on a constrained partial differential equation optimization framework and capable of recovering highly singular potentials.

Hole transport properties for stacked porphyrins are analyzed with density functional theory.

An embedding method for a one-electron reduced density matrix (1-RDM) is proposed.

Despite the fact that B and Al belong to the same group 13 elements, the B₆²⁻ cluster prefers the planar D_2h geometry, whereas Al₆²⁻ favours the O_h structure, which is caused by orbital interactions.

Different choices of initial Kohn Sham wavefunction shape the time-dependent exchange–correlation potential.

The step structure of exact exchange–correlation potentials is linked to the properties of the average local electron energy (ALEE).

Besides molecular electron densities obtained within the Born–Oppenheimer approximation (ρ_B(r)) to represent the environment, the ensemble averaged density (〈ρ_B〉(r)) is also admissible in frozen-density embedding theory (FDET) [Wesolowski, Phys. Rev. A, 2008, 77, 11444].

The S66x8 dataset for noncovalent interactions of biochemical relevance has been re-examined by means of CCSD(F12*)(T), DFT, and SAPT methods.

Ensemble density functional theory (DFT) furnishes a rigorous theoretical framework for describing the non-dynamic electron correlation arising from (near) degeneracy of several electronic configurations.

We investigate a number of formal properties of the adiabatic strictly-correlated electrons (SCE) functional, relevant for time-dependent potentials and for kernels in linear response time-dependent density functional theory.

We present a subsystem TDDFT method which maintains inter-subsystem orbital orthogonality.

Ligand chemical shifts (pNMR shifts) are analyzed using DFT. A large difference in the amide proton shifts of a high-spin Fe(II) complex arises from O → Fe dative bonding which only transfers β spin density to the metal.

Contrary to previous claims, there is no formal need for enforcing external orthogonality in subsystem density-functional theory.

One of the major computational bottlenecks in one-body reduced density matrix functional is the evaluation of the approximate functionals due to a 4-index transformation. For separable functionals, the 4-index transformation can be avoided which leads to a significant better scaling.

4-Component relativistic calculations explore uranium 2p_3/2 ionization and excitation in the isoelectronic series UO₂²⁺, OUN⁺ and UN₂.

The recovery of the total molecular energy from the IQA energy components for a B3LYP wave function is now possible.

A new double hybrid density functional (PWRB95) based on GGA orbitals and RPA is presented and its performance is investigated compared to standard DFT and wavefunction methods.