"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 novel AuH2 molecule has been formed in solid hydrogen by reactions of excited gold atoms from laser ablation and irradiation after thermal evaporation. The X2B2 ground state of the AuH2 molecule is separated by a 53 kcal/mol barrier from the Au(2D) + H2 decomposition products and it is 27 kcal/mol more stable than Au(2D) + H2. The bending modes of AuH2, AuHD, and AuD2 have been observed at 638.1, 570.6, and 457.0 cm-1. These frequencies and the lack of infrared intensity in the stretching modes are in agreement with the results of relativistic ECP DFT, MP2, and CCD calculations. The computed bending potential energy surfaces of three electronic states of AuH2 using CASSCF/MRSDCI methods reveal that there is a barrier for decomposition of the X2B2 ground state to Au(2S) + H2.

The Gold Dihydride Molecule, AuH2: Calculations of Structure, Stability, and Frequencies, and the Infrared Spectrum in Solid Hydrogen†

Raman spectra of alkali metal-iodine matrix reaction products. Resonance Raman spectrum of the iodine molecular anion, I2-

A magnetic circular dichroism (MCD) and absorption study has been made of the 1S (3s2) →1P (3s3p) transition of Mg atoms in Ne, Ar, Kr, and Xe matrices. Triplet structure is observed in the latter three, and a detailed analysis of the MCD shows that this structure results from a splitting of the 1P excited state at a single site. An analysis of the zeroth and first MCD and absorption moments shows that the orbital angular momentum of this 1P state is partially quenched, the quenching factors being approximately 0.65, 0.75, 0.50, and 0.43 in Ne, Ar, Kr, and Xe matrices, respectively. This quenching is necessarily a consequence of out‐of‐state mixing (i.e., orbital mixing outside the atomic 1P excited manifold) and almost certainly reflects strong mixing of the 3p Mg orbitals with noble gas orbitals on neighboring host atoms. An analysis of higher absorption and MCD moments assuming octahedral site symmetry shows a dominant noncubic (Jahn–Teller active) mode contribution to the bandwidth in the three hosts ...

Magnetic circular dichroism of the 1S→1P transition of Mg atoms in noble gas matrices

The simple methylidene (CH2=TiHX) and Grignard-type (CH3TiX) complexes are produced by reaction of methyl chloride and bromide with laser-ablated Ti atoms and isolated in a solid Ar matrix, and they form a persistent photoreversible system via alpha-hydrogen migration between the carbon and titanium atoms. The Grignard-type product is transformed to the methylidene complex upon UV (240 nm 530 nm) irradiation. More stable dimethyl dihalide complexes [(CH3)2TiX2] are also identified, whose relative concentration increases upon annealing and at high methyl halide concentration. The reaction products are identified with three different groups of absorptions on the basis of the behaviors upon broadband photolysis and annealing, and the vibrational characteristics are in a good agreement with DFT computation results.

Formation of CH3TiX, CH2=TiHX, and (CH3)2TiX2 by reaction of methyl chloride and bromide with laser-ablated titanium atoms: photoreversible alpha-hydrogen migration

Lester Andrews

Papers

The Gold Dihydride Molecule, AuH2: Calculations of Structure, Stability, and Frequencies, and the Infrared Spectrum in Solid Hydrogen†

Raman spectra of alkali metal-iodine matrix reaction products. Resonance Raman spectrum of the iodine molecular anion, I2-

Magnetic circular dichroism of the 1S→1P transition of Mg atoms in noble gas matrices

Formation of CH3TiX, CH2=TiHX, and (CH3)2TiX2 by reaction of methyl chloride and bromide with laser-ablated titanium atoms: photoreversible alpha-hydrogen migration

Matrix infrared spectrum and vibrational analysis of the chlorosyl fluoride intermediate