"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

Hydrazine, N/sub 2/H/sub 4/, and its reactions with HF, F/sub 2/, and O/sub 3/ have been studied in an argon matrix. Vibrational assignments have been made for hydrazine, including clarification of the /nu//sub 6/, /nu//sub 10/, and 2/nu//sub 7/ bands. Complexation of N/sub 2/H/sub 4/ with HF produced a strong band at 2928 cm/sup /minus/1/ (/nu//sub s/(HF)) and sharp bands at 940 and 922 cm/sup /minus/1/ (/nu//sub 1/(HF)), as well as several perturbed N/sub 2/H/sub 4/ submolecule absorptions; the frequencies of these bands suggest a chelated structure similar to that for the NH/sub 2/OH-HF complex. Hydrazine and fluorine reacted during deposition to give the NH/sub 2/NHF-HF complex (/nu//sub s/ = 3113 cm/sup /minus/1/, /nu//sub 1/ = 726, 680 cm/sup /minus/1/). Reaction of hydrazine and ozone produced hydroxyhydrazine, NH/sub 2/NHOH, and minor products during deposition; photolysis increased the yield of hydroxyhydrazine. Evidence for an intramolecular hydrogen bond was found for NH/sub 2/NHOH. This matrix study presents the first spectroscopic evidence for both NH/sub 2/NHF and NH/sub 2/NHOH. 32 references, 3 figures, 4 tables.

Infrared spectra of hydrazine and products of its reactions with HF, F2, and O3 in solid argon

Infrared spectra of HNF/sub 2/, NF/sub 3/, PF/sub 3/, and PCl/sub 3/ and their complexes with HF were observed in solid argon matrices. An asymmetric structure was deduced for (HNF/sub 2/)/sub 2/ based on comparison with HNF/sub 2/ spectra. Complexation of these bases with HF produced the following bands: HNF/sub 2/, 3681 cm/sup -1/ (nu/sub s/) and 516 and 498 cm/sup -1/ (nu/sub l/); NF/sub 3/, 3913 cm/sup -1/ (nu/sub s/) and 246 cm/sup -1/ (nu/sub l/); PF/sub 3/, 3890 cm/sup -1/ (nu/sub s/) and 258 cm/sup -1/ (nu/sub l/); PCl/sub 3/, 3868 cm/sup -1/ (nu/sub s/). The spectra suggested the formation of a hydrogen bond between HF and the N or P lone pair for all four complexes. A direct correlation between proton affinity and nu/sub s/ was found for fluoro-substituted amines, allowing prediction of the HNF/sub 2/ proton affinity as 163 +- 5 kcalmol and that of NH/sub 2/F as 181 +- 5 kcalmol. Basicity trends in nitrogen and phosphorus compounds are discussed.

Infrared spectra of fluoroimide, nitrogen trifluoride, phosphorus trifluoride, and phosphorus trichloride and complexes with hydrogen fluoride in solid argon

Laser-ablated vanadium atoms have been reacted with NO molecules during condensation in excess argon. Absorptions due to NVO (998.1, 906.4 cm-1), V−η1-NO (1606.0 cm-1), V−η2-NO (1075.7 cm-1) and V−(η2-NO)2 (1119.6,1153.8 cm-1) are observed and identified via isotopic substitution and DFT calculations. Higher nitrosyls are also formed on annealing. On the basis of the observed isotopic splitting, bands at 1614.5 and 1736.8 cm-1 are assigned to antisymmetric and symmetric N−O vibrations of the C2v dinitrosyl V(NO)2, and 1715.1 and 1850.6 cm-1 bands are assigned to the analogous vibrations of V(NO)3 with C3v symmetry. The observation of (VO), (N2O) and (N2), (VO2) complexes suggests that V atoms also react with (NO)2 in these experiments.

Reactions of Laser-Ablated Vanadium Atoms with Nitric Oxide. Infrared Spectra and Density Functional Calculations on NVO, V−η1-NO, V−(η1-NO)2, V−(η1-NO)3, and V−η2-NO

Lester Andrews

Papers

Infrared spectra of hydrazine and products of its reactions with HF, F2, and O3 in solid argon

Infrared spectra of fluoroimide, nitrogen trifluoride, phosphorus trifluoride, and phosphorus trichloride and complexes with hydrogen fluoride in solid argon

Reactions of Laser-Ablated Vanadium Atoms with Nitric Oxide. Infrared Spectra and Density Functional Calculations on NVO, V−η1-NO, V−(η1-NO)2, V−(η1-NO)3, and V−η2-NO

Infrared Spectra, Structure, and Bonding of the Group 6 and Ammonia M:NH3, H2N−MH, and N≡MH3 Reaction Products in Solid Argon

Matrix infrared spectra of the ammonia-hydrogen cyanide and ammonia-hydrogen cyanide (1:2) complexes in solid argon