"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 HF were bombarded by low energy electrons (150–400 eV) from a thermionic electron source during condensation at 12 K. Several polyfluoride anions, which have extremely strong hydrogen bonds, were characterized using matrix infrared spectroscopy. Three principal ions were trapped in the argon matrix: HF−2 (1377 cm−1), H2F−3 (1815 cm−1), and ArnH+ (904 cm−1). Electron impact experiments performed with HF/DF mixtures gave counterpart absorptions: DF−2 (965 cm−1), HDF−3 (1707 cm−1), D2F−3 (1391 cm−1), and Arn D+ (644 cm−1). The 1377 cm−1 matrix band is assigned to ν3 of linear, centrosymmetric HF−2, based on agreement with solid state and matrix ion pair spectra, and ab initio calculations, and a proper H/D ratio (1.427) for a linear centrosymmetric species. However, this assignment challenges the recent 1848 cm−1 gas phase assignment to ν3 of HF−2 using laser spectroscopy; the 1848 cm−1 absorption exhibits an H/D ratio (1.323) that is too low for the ν3 vibration of centrosymmetric H...

FTIR spectra of the HF−2 and H2F−3 anions isolated in solid argon and neon

One-to-one complexes between Li, Na, K, and Cs atoms and NH/sub 3/ have been studied by using matrix IR spectroscopy. New bands at 1133, 1079, 1064, and 1049 cm/sup -1/ are assigned to perturbed nu/sub 2/ modes, and bands at 3277, 3294, 3292, and 3287 cm/sup -1/ are assigned to the perturbed nu/sub 1/ ammonia submolecule modes of the Li--NH/sub 3/, Na--NH/sub 3/, K--NH/sub 3/, and Cs--NH/sub 3/ complexes, respectively. The corresponding bands for K and /sup 15/NH/sub 3/, NH/sub 2/D, NHD/sub 2/, and ND/sub 3/ complexes are also assigned. The intensity ratios of nu/sub 1/ to nu/sub 2/ for the ammonia submolecule modes in the Li, Na, K, and Cs complexes are larger by factors of 15, 20, 30, and 35, respectively, than the corresponding ratio for isolated ammonia. The intensification and position of nu/sub 1/ in the complex and the alkali metal-ammonia interaction are consistent with calculations of a very small ammonia ..-->.. metal charge transfer where the alkali atom acts as a weak Lewis acid for Li and Na. The increased ammonia interaction with K and Cs may suggest a possible acid-base role reversal for the heavier alkali complexes. At higher metal/ammonia concentrations higher aggregate bands ofmore » (M)/sub n/--NH/sub 3/ nature are also observed.« less

Infrared spectra of alkali metal atom-ammonia complexes in solid argon

Calculations and matrix infrared spectra of terminal borylene complexes FB=MF2.

Laser-ablated Y and La atoms react with nitrogen to produce metal nitrides and dinitrogen complexes, whereas thermally evaporated Y and La atoms form only dinitrogen complexes. The ligated mononitride complexes (NN)xYN and (NN)xLaN at 771.6 and 761.7 cm-1 in solid nitrogen are identified from nitrogen-15 shifts. These complexes predict gas-phase fundamentals near 800 and 790 cm-1 respectively for YN and LaN. The (YN)2 and (LaN)2 molecules and dinitrogen complexes are also identified from nitrogen-15 shifts and result from the reaction of two metal atoms with a single dinitrogen molecule involving the Y(N2) and La(N2) intermediate species. The same saturated (YN)2(NN)x and (LaN)2(NN)x dinitrogen complexes are prepared on annealing solid argon containing 2% N2 and deposition in pure nitrogen. The growth of ligated (YN)2(NN)x and (LaN)2(NN)x on annealing suggests that this nitrogen fixation reaction involves little activation energy.

Lester Andrews

Papers

FTIR spectra of the HF−2 and H2F−3 anions isolated in solid argon and neon

Infrared spectra of alkali metal atom-ammonia complexes in solid argon

Calculations and matrix infrared spectra of terminal borylene complexes FB=MF2.

Reactions of Yttrium and Lanthanum Atoms with Nitrogen. Infrared Spectra of the Metal Nitrides and Dinitrogen Complexes in Solid Argon and Nitrogen

Matrix Raman spectrum of the fluorine molecular anion, F2-