"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

Argon diluted samples of H2 and ClF were codeposited at 10 K, and no reaction was observed. Photolysis produced a sharp 2834.5, 2832.5 cm−1 doublet, in agreement with (HF)(HCl) dimer from HF and HCl codeposition experiments. Irradiation at 14–16 K markedly increased the mixed dimer and produced weak monomer and dimer bands of HCl and HF, mixed trimer absorptions, and a sharp band at 3857.9 cm−1 for the Cl‐‐HF radical complex. In similar experiments with HD, two mixed dimers, (HF)(DCl) and (HCl)(DF), were formed; likewise, photolyzing D2 with ClF produced two mixed dimers of the form (DF)(DCl) and (DCl)(DF). In the H2 and BrF system, photolysis produced a sharp absorption at 3814.6 cm−1, in agreement with (HBr)(HF) dimer from HBr and HF codeposition experiments, and a new 3830.5 cm−1 band due to the Br‐‐HF radical complex. In a parallel study with HD, two mixed dimers, (HBr)(DF) and (DBr)(HF), were observed while only one mixed dimer, (DBr)(DF), was formed by BrF and D2. In complementary experiments with H...

Photochemical reactions of ClF and BrF with hydrogen in solid argon. Infrared spectra of mixed hydracid dimers

Matrix reactions of fluorine with chlorine, bromine, and iodine. Infrared detection of the XF2, X2F2, and X2F species

Infrared spectrum and vibrational potential function of the chlorite anion in the matrix-isolated M+ClO2− species

Sulfur diatomic molecules were reacted with laser ablated Cu, Ag, and Au atoms in excess argon and condensed at 7 K. Several reaction products were identified for each metal from matrix infrared spectra through sulfur-34 isotopic shifts, spectra of sulfur isotopic mixtures, and frequencies calculated by density functional theory. The linear centrosymmetric 63CuS2, 65CuS2, and AuS2 metal disulfide molecules were observed at 508.7, 504.8, and 455.9 cm−1, respectively. The bent CuSS, AgSS, and AuSS isomers were identified from 608.6, 580.7, and 601.1 cm−1 S–S stretching fundamentals, respectively. These group 11 metals also formed cyclic tetrasulfur molecules, MS4, in contrast to group 10 metal atoms, which formed side-bonded disulfur complexes M(S2)2.

Infrared spectra and density functional theory calculations of coinage metal disulfide molecules and complexes

Samples formed by codepositing S2 from a superheater source with Ar/O2 on a 10 K substrate exhibit very strong 1403.0-cm-1 and weaker 725.5-cm-1 infrared absorptions. Photolysis decreases these bands slightly and produces SO2 and S2O. The infrared bands show 18O2 and 34S2 shifts appropriate for O−O and S−S fundamental vibrations, and triplet absorptions in mixed isotopic experiments suggesting two equivalent O and two equivalent S atoms in the product complex. Similar results were obtained for Se2 and O2; new absorptions appeared at 1404.5 and 391 cm-1. Ab initio calculations at the SCF, CISD, and CCSD levels of theory failed to find a complex with the observed spectroscopic properties. However, calculations with the BP density functional characterized a singlet (S2)(O2) parallelogram structure bound by 15.6 kJ/mol relative to triplet S2 and O2 with the O−O stretching frequency red-shifted 187 cm-1 and the S−S fundamental blue-shifted 20 cm-1. This weakly bound (S2)(O2) complex is chemically intermediate ...

Lester Andrews

Papers

Photochemical reactions of ClF and BrF with hydrogen in solid argon. Infrared spectra of mixed hydracid dimers

Matrix reactions of fluorine with chlorine, bromine, and iodine. Infrared detection of the XF2, X2F2, and X2F species

Infrared spectrum and vibrational potential function of the chlorite anion in the matrix-isolated M+ClO2− species

Infrared spectra and density functional theory calculations of coinage metal disulfide molecules and complexes

Formation, Spectroscopy, Photochemistry, and Quantum Chemistry of the (S2)(O2) Complex in Solid Argon