We present an analysis of the performances of a parameter free density functional model (PBE0) obtained combining the so called PBE generalized gradient functional with a predefined amount of exact exchange. The results obtained for structural, thermodynamic, kinetic and spectroscopic (magnetic, infrared and electronic) properties are satisfactory and not far from those delivered by the most reliable functionals including heavy parameterization. The way in which the functional is derived and the lack of empirical parameters fitted to specific properties make the PBE0 model a widely applicable method for both quantum chemistry and condensed matter physics.

Toward reliable density functional methods without adjustable parameters: The PBE0 model

We present the theoretical and technical foundations of the Amsterdam Density Functional (ADF) program with a survey of the characteristics of the code (numerical integration, density fitting for the Coulomb potential, and STO basis functions). Recent developments enhance the efficiency of ADF (e.g., parallelization, near order-N scaling, QM/MM) and its functionality (e.g., NMR chemical shifts, COSMO solvent effects, ZORA relativistic method, excitation energies, frequency-dependent (hyper)polarizabilities, atomic VDD charges). In the Applications section we discuss the physical model of the electronic structure and the chemical bond, i.e., the Kohn–Sham molecular orbital (MO) theory, and illustrate the power of the Kohn–Sham MO model in conjunction with the ADF-typical fragment approach to quantitatively understand and predict chemical phenomena. We review the “Activation-strain TS interaction” (ATS) model of chemical reactivity as a conceptual framework for understanding how activation barriers of various types of (competing) reaction mechanisms arise and how they may be controlled, for example, in organic chemistry or homogeneous catalysis. Finally, we include a brief discussion of exemplary applications in the field of biochemistry (structure and bonding of DNA) and of time-dependent density functional theory (TDDFT) to indicate how this development further reinforces the ADF tools for the analysis of chemical phenomena. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 931–967, 2001

Chemistry with ADF

"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

Over the past decade the theoretical description of surface reactions has undergone a radical development. Advances in density functional theory mean it is now possible to describe catalytic reactions at surfaces with the detail and accuracy required for computational results to compare favourably with experiments. Theoretical methods can be used to describe surface chemical reactions in detail and to understand variations in catalytic activity from one catalyst to another. Here, we review the first steps towards using computational methods to design new catalysts. Examples include screening for catalysts with increased activity and catalysts with improved selectivity. We discuss how, in the future, such methods may be used to engineer the electronic structure of the active surface by changing its composition and structure.

Towards the computational design of solid catalysts

Starting from an analysis of the low-density and large gradient regions which dominate van der Waals interactions, we propose a modification of the exchange functional introduced by Perdew and Wang, which significantly enlarges its field of applications. This is obtained without increasing the number of adjustable parameters and retaining all the asymptotic and scaling properties of the original model. Coupling the new exchange functional to the correlation functional also proposed by Perdew and Wang leads to the mPWPW model, which represents the most accurate generalized gradient approximation available until now. We next introduce an adiabatic connection method in which the ratio between exact and density functional exchange is determined a priori from purely theoretical considerations and no further parameters are present. The resulting mPW1PW model allows to obtain remarkable results both for covalent and noncovalent interactions in a quite satisfactory theoretical framework encompassing the free elec...

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Exchange functionals with improved long-range behavior and adiabatic connection methods without adjustable parameters: The mPW and mPW1PW models

Potential Energy Surfaces of the Gas-Phase S N 2 Reactions X - +CH 3 X=XCH 3 +X - (X=F,Cl,Br,I): A Comparative Study by Density Functional Theory and ab Initio Methods.

Atomic reference energies for density functional calculations

Comparison is made of the interaction of NO2 with Cu+ ions in the gas phase and inside zeolites using density functional theory (B3LYP functional). The zeolite is represented by a tritetrahedra model embedded in the periodic structure of zeolite ZSM-5 and by a free space cluster model. Both models yield virtually the same results. Cu+ is coordinated to two oxygen atoms of the zeolite framework only. For the complexes with NO2, several minima and transition structures on the potential energy surfaces are localized. The naked Cu+ ion preferentially binds NO2 in the η1-O trans mode, while in zeolites the Cu+ site binds NO2 in a 2η-O,O coordination. For the 2η-O,O structure the binding is three to four times stronger in the zeolite (43 kcal/mol) than in the gas phase which is due to a three-body zeolite frameworkCu+ ion−NO2 interaction. d10−s1d9 promotion leads to a more favorable orbital interaction between Cu+ and NO2 in the 2A‘‘ state and, due to reduced repulsion, to a stronger electrostatic interaction b...

Coordination of Cu+ Ions to Zeolite Frameworks Strongly Enhances Their Ability To Bind NO2. An ab Initio Density Functional Study

The coordination of carbon dioxide to first transition row metal cations and the insertion reaction of the metal into one CO bond of carbon dioxide have been studied theoretically. The geometry and the vibrational frequencies of the M+−CO2 and OM+CO structures have been determined using the hybrid three-parameter B3LYP density functional approach. Binding energies have also been determined at the CCSD(T) level using large basis sets. The linear end-on M+−OCO structure is the most favorable coordination for CO2, due to the electrostatic nature of the bonding. In the inserted OM+CO structures, the bonding arises from the electrostatic interaction between the ground state of OM+ and CO. For the early transition metals (Sc+, Ti+, and V+), the insertion reaction is exothermic and the inserted OM+CO structure is more stable than the linear M+−OCO isomer, because of the very strong MO+ bond that is formed.

Theoretical study of m+-co2 and om+co systems for first transition row metal atoms

The adsorption of NH3 and H2O in acidic chabazite has been studied with the B3LYP method within the cluster approach (5T, 48T clusters) and the periodic approach adopting a Si/Al = 11/1 chabazite and a basis set of polarized double-ζ quality. The 5T cluster has been treated fully ab initio at the B3LYP level whereas the 48T cluster has been treated with the ONIOM2 scheme using B3LYP as the high level of theory and the MNDO, AM1, and HF/3-21G methods as low levels of theory. Periodic calculations show that the adsorption of NH3 in acidic chabazite takes place through an ion pair (NH4+−CHA-) structure, the computed adsorption energy being −32 kcal/mol. The adsorption of H2O leads to a hydrogen bonded (H2O−HCHA) complex with the computed adsorption energy of −20 kcal/mol. All ONIOM combinations provide similar structures to those obtained with periodic calculations. Adsorption energies, however, are sensitive to the low level used, especially for NH3. The ONIOM B3LYP:HF/3-21G method is the one that provides ...

Vicenç Branchadell

Papers

Potential Energy Surfaces of the Gas-Phase S N 2 Reactions X - +CH 3 X=XCH 3 +X - (X=F,Cl,Br,I): A Comparative Study by Density Functional Theory and ab Initio Methods.

Atomic reference energies for density functional calculations

Coordination of Cu+ Ions to Zeolite Frameworks Strongly Enhances Their Ability To Bind NO2. An ab Initio Density Functional Study

Theoretical study of m+-co2 and om+co systems for first transition row metal atoms

Adsorption of NH3 and H2O in Acidic Chabazite. Comparison of ONIOM Approach with Periodic Calculations