"Chemists familiar with conventional quantum mechanics will applaud and benefit greatly from this particularly instructive, thorough and clearly written exposition of density functional theory: its basis, concepts, terms, implementation, and performance in diverse applications. Users of DFT for structure, energy, and molecular property computations, as well as reaction mechanism studies, are guided to the optimum choices of the most effective methods. Well done!" Paul von RaguE Schleyer "A conspicuous hole in the computational chemist's library is nicely filled by this book, which provides a wide-ranging and pragmatic view of the subject.[...It] should justifiably become the favorite text on the subject for practioneers who aim to use DFT to solve chemical problems." J. F. Stanton, J. Am. Chem. Soc. "The authors' aim is to guide the chemist through basic theoretical and related technical aspects of DFT at an easy-to-understand theoretical level. They succeed admirably." P. C. H. Mitchell, Appl. Organomet. Chem. "The authors have done an excellent service to the chemical community. [...] A Chemist's Guide to Density Functional Theory is exactly what the title suggests. It should be an invaluable source of insight and knowledge for many chemists using DFT approaches to solve chemical problems." M. Kaupp, Angew. Chem.

A Chemist's Guide to Density Functional Theory

A scheme that reduces the calculations of ground-state properties of systems of interacting particles exactly to the solution of single-particle Hartree-type equations has obvious advantages. It is not surprising, then, that the density functional formalism, which provides a way of doing this, has received much attention in the past two decades. The quality of the energy surfaces calculated using a simple local-density approximation for exchange and correlation exceeds by far the original expectations. In this work, the authors survey the formalism and some of its applications (in particular to atoms and small molecules) and discuss the reasons for the successes and failures of the local-density approximation and some of its modifications.

The density functional formalism, its applications and prospects

The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.

The Halogen Bond

The detection methods and generation mechanisms of the intrinsic reactive oxygen species (ROS), i.e., superoxide anion radical (•O2–), hydrogen peroxide (H2O2), singlet oxygen (1O2), and hydroxyl radical (•OH) in photocatalysis, were surveyed comprehensively. Consequently, the major photocatalyst used in heterogeneous photocatalytic systems was found to be TiO2. However, besides TiO2 some representative photocatalysts were also involved in the discussion. Among the various issues we focused on the detection methods and generation reactions of ROS in the aqueous suspensions of photocatalysts. On the careful account of the experimental results presented so far, we proposed the following apprehension: adsorbed •OH could be regarded as trapped holes, which are involved in a rapid adsorption–desorption equilibrium at the TiO2–solution interface. Because the equilibrium shifts to the adsorption side, trapped holes must be actually the dominant oxidation species whereas •OH in solution would exert the reactivity...

Generation and Detection of Reactive Oxygen Species in Photocatalysis

: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Anhydrous B(OH)3 was pressed into a pellet and sublimed at room temperature under vacuum to give molecular B(OH)3 for argon matrix infrared study. The spectrum showed sharp fundamentals without the effect of hydrogen bonding observed in the solid. Fermi resonances were characterized for two fundamentals. The observed frequencies for B(OH)3 and the three deuterium substituted molecules are in agreement with values from self‐consistent field/double zeta plus polarization (SCF/DZP) calculations allowing for appropriate scale factors. The major thermal decomposition products from pulsed laser evaporation of B(OH)3 were H2O, B2O3, and HOBO. Molecular HOBO was characterized by a strong 2020 cm−1 fundamental, which was confirmed by SCF/DZP calculations.

Infrared spectra of molecular B(OH)3 and HOBO in solid argon

This paper discusses vibronic absorption spectra of S{sub 3} and S{sub 4} in solid argon which reveal that S{sub 4} has two different photoisomers, green- and red-absorbing species. S{sub 3} has three argon matrix trapping sites based on annealing, vibrational spacings, and isotopic shifts. {nu}{sub 1}{prime} and {nu}{sub 2}{prime} are also determined. 23 refs., 8 figs., 3 tabs.

Vibronic absorption spectra of sulfur (S3 and S4) in solid argon

Laser ablated Zn and Cd atoms contain sufficient excess energy to react directly with O2 to produce the subject molecules. A zinc isotopic triplet at 769.2, 766.8, 764.5 cm−1 gave a doublet with statistical isotopic oxygen confirming the identification of ZnO. A previous resonance Raman fundamental at 769 cm−1 is reassigned to ZnO, which suggests a green visible absorption for the zinc oxide molecule. A zinc isotopic triplet at 748.2, 744.4, 740.9 cm−1 produced a triplet with statistical isotopic oxygen and isotopic shifts appropriate for the linear OZnO dioxide molecule. Cadmium is less reactive than zinc; infrared absorptions at 645.1 and 626.6, 625.4 cm−1 exhibit proper oxygen isotopic behavior for assignment to CdO and OCdO and the latter showed partially resolved cadmium isotopic splittings.

Reactions of laser-ablated Zn and Cd atoms with O2: Infrared spectra of ZnO, OZnO, CdO, and OCdO in solid argon

Argon matrix samples containing O2 and Cl2 have been bombarded with 2.0 keV protons and deuterons during condensation at 15°K. In the oxygen experiments, bands due to O3 and HO2 appeared. Of most interest is isolated O−3 at 804.3 cm−1. Deuteron radiolysis produced increased yields of the 644 cm−1 band which is confirmed as a DAr+n species. Proton and deuteron radiolysis of chlorine−containing samples produced HCl2x and DCl2x in high yields. Owing to the strong electron scavenging capability of chlorine, these species are probably anions.

Proton and deuteron radiolysis of argon matrix samples of O2 and Cl2. Infrared spectra of charged species

Uranium atoms excited by laser ablation react with CO in excess neon to produce the novel CUO molecule, which forms distinct Ng complexes (Ng = Ar, Kr, Xe) when the heavier noble gases are added. The CUO(Ng) complexes are identified through CO isotopic and Ng substitution on the neon matrix infrared spectra and by comparison to DFT frequency calculations. The U−C and U−O stretching frequencies of CUO(Ng) complexes are slightly red-shifted from frequencies for the 1Σ+ CUO ground state, which identifies singlet ground state CUO(Ng) complexes. In solid neon the CUO molecule is also a complex CUO(Ne)n, and the CUO(Ne)n-1(Ng) complexes are likewise specified. The next singlet CUO(Ne)x(Ng)2 complexes in excess neon follow in like manner. However, the higher CUO(Ne)x(Ng)n complex (n = 3, 4) stretching modes approach pure argon matrix CUO(Ar)n values and isotopic behavior, which are characterized as triplet ground state complexes by DFT frequency calculations. This work suggests that the singlet−triplet crossing ...

On the noble-gas-induced intersystem crossing for the CUO molecule: experimental and theoretical investigations of CUO(Ng)n (Ng = Ar, Kr, Xe; n = 1, 2, 3, 4) complexes in solid neon.

Lester Andrews

Papers

Infrared spectra of molecular B(OH)3 and HOBO in solid argon

Vibronic absorption spectra of sulfur (S3 and S4) in solid argon

Reactions of laser-ablated Zn and Cd atoms with O2: Infrared spectra of ZnO, OZnO, CdO, and OCdO in solid argon

Proton and deuteron radiolysis of argon matrix samples of O2 and Cl2. Infrared spectra of charged species

On the noble-gas-induced intersystem crossing for the CUO molecule: experimental and theoretical investigations of CUO(Ng)n (Ng = Ar, Kr, Xe; n = 1, 2, 3, 4) complexes in solid neon.