Density functional theory

Abstract

Density functional theory (DFT) finds increasing use in applications related to biological systems. Advancements in methodology and implementations have reached a point where predicted properties of reasonable to high quality can be obtained. Thus, DFT studies can complement experimental investigations, or even venture with some confidence into experimentally unexplored territory. In the present contribution, we provide an overview of the properties that can be calculated with DFT, such as geometries, energies, reaction mechanisms, and spectroscopic properties. A wide range of spectroscopic parameters is nowadays accessible with DFT, including quantities related to infrared and optical spectra, X-ray absorption and Mössbauer, as well as all of the magnetic properties connected with electron paramagnetic resonance spectroscopy except relaxation times. We highlight each of these fields of application with selected examples from the recent literature and comment on the capabilities and limitations of current methods.

Recent Progresses in Understanding of Co-Based Fischer–Tropsch Catalysis by Means of Transient Kinetic Studies and Theoretical Analysis

“…There are two used methods to construct the DFT models containing defects, where one is creating the defect by removing certain atoms on the low Miller index orientations (such as stepped Co (0001)) [33,36,116,120] and the other is using the model based on the high Miller index orientations that produce corrugated surfaces [113,118,131]. Ge et al [118] studied the effect of defects on CO dissociation by employing the Co (11)(12)(13)(14)(15)(16)(17)(18)(19)(20), Co (10-12) and Co (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24) as model surfaces shown in Fig. 3, in which Co (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) is more open and corrugated than Co (0001), Co (10-12) contains steps and Co (11)(12)(13)(14)(15)…”

“…Ge et al [118] studied the effect of defects on CO dissociation by employing the Co (11)(12)(13)(14)(15)(16)(17)(18)(19)(20), Co (10-12) and Co (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24) as model surfaces shown in Fig. 3, in which Co (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) is more open and corrugated than Co (0001), Co (10-12) contains steps and Co (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24) contains double steps and kinks. As expected, the barrier of CO dissociation decreases in the order Co (11)…”

“…2. With the advancement of sophisticated computational chemistry techniques, the intricate electronic-structure calculations based on density functional theory (DFT) have recently been widely used to provide fundamental data regarding the surface reaction, which can be a complement to the experimental analysis for understanding of reaction mechanisms [23][24][25][26]. More importantly, it can distinguish between those possibilities that were left open, such as various reaction pathways.…”

Introducing a closed system approach for the investigation of chemical steps involving proton and electron transfer; as illustrated by a copper-based water oxidation catalyst

“…18,19 Traditionally, catalytic cycles are examined computationally by comparing the free energies of the proposed catalytic intermediates and then, usually, assigning the thermodynamically most favourable cycle as the most likely catalytic cycle. 12,14,[20][21][22][23] This examination often uses an implicit solvent model or correction factors to account for protons and electrons removed in the catalytic step itself, 14,20,22,[24][25][26] while the more involved methods which do include explicit solvent molecules are very time-consuming. [27][28][29] Using correction factors prevents direct comparisons of the intermediates as the compared intermediates usually contain differing numbers of protons and electrons.…”

Predicting ESR Peaks in the 4d and 5d Transition Metal Ion Complexes by NMR, ESR and NQR Parameters: A DFT Study

“…Only a limited research work had been done in the experimental determination of number of ESR peaks in complexes of 4d and 5d metal ions [1][2][3][4][5] like Zr (III) [6][7][8] ,Hf (III) [7][8][9] ; Nb (IV) [10][11][12] , Ta (IV) 9 ; Tc (II) 9, 13, 14 , Re (II ) [15][16][17] ; Ru (III) [18][19][20][21][22][23][24] , Os (III) [18][19][20]24 ; Rh (IV) 25-27 , Ir (IV) 26,27 which formed five congeners of 2 nd and 3 rd transition series.…”