"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

The first band in the He(I) photoelectron spectrum of the CH2Cl free radical

Various xenon/fluorine mixtures were photolyzed in solid argon matrices and examined in the infrared spectral region with either a Fourier transform spectrometer or with a grating spectrometer. After photolysis, a strong peak was observed at 215 cm−1 in addition to the known XeF2(ν3) peak at 549 cm−1. The appearance of the same two bands in Ar matrices containing the vapors over XeF2 indicated the assignment of the 215 cm−1 band to XeF2(ν2). The fundamental of XeF was not observed either because it is masked by the XeF2(ν2) peak or because it has a small infrared absorption coefficient.

A search for the infrared fundamental of matrix-isolated XeF

Infrared observation of perfluoropropene cation in solid argon

Reactions of laser-ablated rhodium atoms with molecular nitrogen in excess neon produce the rhodium nitrogen complexes Rh(NN)x (x = 1−3) and their counterpart anions through the capture of ablated electrons. The observed absorption bands are identified by isotopic substitution and DFT calculations of vibrational fundamentals. The N−N stretching fundamental at 2162.0 cm-1 for RhNN and the antisymmetric N−N mode for Rh(NN)2 at 2199.3 cm-1 in solid neon are in accord with earlier argon matrix assignments. Three N−N stretching frequencies at 2185.2, 2203.3, and 2235.6 cm-1 are assigned to Rh(NN)3, which is calculated to have a T-shaped structure with a 2A1 ground state. The photosensitive Rh(NN)x- (x = 1−3) anions are eliminated with CCl4 doping to capture ablated electrons.

Rhodium Dinitrogen Complexes Rh(NN)x (x = 1−3) and Anions: Matrix Infrared Spectra and DFT Calculations

Hydrogen is flowed through a mild tesla-coil discharge and trapped at 3.8 K: New infrared absorptions of H2 are induced by interaction with trapped H atoms and H− anions. High purity parahydrogen and orthodeuterium samples are 1%–9% reconverted depending on the discharge pressure and recombination of atoms. Annealing the solid samples to 7 K reveals growth in p-H2 induced by o-H2, which shows that H atom recombination produces thermal nuclear spin populations. Similar results are found in discharge experiments with HD and on annealing solid HD. The observed increase in induced HD absorption by J=1, H2 and D2 molecules formed on recombination gives ≈1% for the H[D] atom concentration in our solid HD samples.

Lester Andrews

Papers

The first band in the He(I) photoelectron spectrum of the CH2Cl free radical

A search for the infrared fundamental of matrix-isolated XeF

Infrared observation of perfluoropropene cation in solid argon

Rhodium Dinitrogen Complexes Rh(NN)x (x = 1−3) and Anions: Matrix Infrared Spectra and DFT Calculations

A discharge investigation of hydrogen and deuterium atom formation, and parahydrogen and orthodeuterium reconversion.