"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 matrix reaction of lithium atoms and carbon tetrachloride produces the CCl3 radical followed by secondary reaction of Li with CCl3 to yield a sufficient concentration of dichlorocarbene for infrared spectral study. Natural chlorine isotopes, carbon‐13 and bromine substitution, and loss of CCl2 absorptions accompanied by growth of C2Cl4 absorptions on sample warming furnish convincing evidence that dichorocarbene is isolated in the argon matrix. Assignments of the C‐Cl stretching vibrations for the 12C35Cl2, 12C35Cl37Cl, 13C35Cl2, and 12C35Cl37Cl species are supported by normal coordinate calculations. For the most abundant isotopic species, ν1 = 719.5 and ν3 = 745.7 cm−1, and ν2, the weak bending mode, was not detected. The stretching force constants Fτ = 2.86 mdyn / A and Fττ = 0.27 mdyn / A indicate that C‐Cl single bonds are present in dichlorocarbene, making it unlikely that the electron deficiency of the carbon atom is relieved by pi bonding with chlorine.

Infrared Spectrum of Dichlorocarbene in Solid Argon

Simple N UF3 and P UF3 molecules with triple bonds to uranium

Multiconfigurational quantum chemical methods (complete active space self-consistent field (CASSCF)/second-order perturbation theory (CASPT2)) have been used to study the agostic interaction between the metal atom and H(C) in the methylidene metal dihydride complexes H2MCH2, where M is a second row transition metal or the actinide atoms Th or U. The geometry of some of these complexes is highly irregular due to the formation of a three center bond CH center dot center dot center dot M, where the electrons in the CH bond are delocalized onto empty or half empty orbitals of d- or f-type on the metal. No agostic interaction is expected when M = Y, where only a single bond with methylene can be formed, or when M = Ru, because of the lack of empty electron accepting metal valence orbitals. The largest agostic interaction is found in the Zr and U complexes.

Agostic Interaction in the Methylidene Metal Dihydride Complexes H2MCH2 (M = Y, Zr, Nb, Mo, Ru, Th, or U)

Calculations via scalar-relativistic density functional theory (DFT) and ab initio CCSD(T) methodologies are used to explore the possibility of direct interactions between molecular UO2 and Ar atoms. The 3Hg electronic state of UO2, which is an excited state of the isolated molecule, exhibits significant bonding to Ar in the model complexes UO2(Ar) and UO2(Ar)5. The calculated vibrational frequencies of ground-state 3Φu UO2 and UO2(Ar)5 with an (fφ)1(fδ)1 electron configuration agree well with the observed frequencies of UO2 in solid neon and solid argon, respectively. The results strongly suggest that the ground electron configuration of UO2 changes from 5f17s1 to 5f2 when the matrix host is changed from neon to argon.

On the electronic structure of molecular UO2 in the presence of Ar atoms: evidence for direct U-Ar bonding.

Laser-ablated iron atoms have been reacted with CO molecules during condensation in excess argon The FeCO molecule is observed at 19220 cm−1 in solid argon based on concentration studies, isotopic shifts, and density functional theory frequency calculations; the argon matrix redshifts this band 270 cm−1 (14%) from the high-resolution gas phase measurement Absorptions at 18792 and 19848 cm−1 are assigned from isotopic substitution and density functional theory frequency calculations to the antisymmetric and symmetric vibrations of a bent Fe(CO)2 molecule in the matrix The Fe(CO)x (x=3,4,5) molecules are also observed on annealing in agreement with earlier matrix work Iron carbonyl ions were also produced and trapped: photosensitive absorptions at 17703, 17219, 18150, 17865, and 18535 cm−1 are assigned to FeCO−, Fe(CO)2−, Fe(CO)3−, and Fe(CO)4−, respectively, and a weak photosensitive 20815 cm−1 band is assigned to FeCO+ Polynuclear metal carbonyls were also formed on annealing; based on different CO concentration and laser power experiments and isotopic substitution, an 18977 cm−1 absorption is assigned to Fe2CO and a 19485 cm−1 band to Fe3CO

Reactions of laser-ablated iron atoms with carbon monoxide: Infrared spectra and density functional calculations of FexCO, Fe(CO)x, and Fe(CO)x− (x=1,2,3) in solid argon

Lester Andrews

Papers

Infrared Spectrum of Dichlorocarbene in Solid Argon

Simple N UF3 and P UF3 molecules with triple bonds to uranium

Agostic Interaction in the Methylidene Metal Dihydride Complexes H2MCH2 (M = Y, Zr, Nb, Mo, Ru, Th, or U)

On the electronic structure of molecular UO2 in the presence of Ar atoms: evidence for direct U-Ar bonding.

Reactions of laser-ablated iron atoms with carbon monoxide: Infrared spectra and density functional calculations of FexCO, Fe(CO)x, and Fe(CO)x− (x=1,2,3) in solid argon