Amsterdam Density Functional method

The potential energy surfaces for the SN2 reactions at carbon, silicon, and phosphorus have been calculated using the Amsterdam Density Functional method with the... 

There has been much recent progress in the application of density functional theory (DFT) to the calculation of shift tensors, and several methods are presently available. The sum-over-state (SOS) DFT method developed by Malkin et al. (70) does not explicitly include the current density, but it has been parametrized to improve numerical accuracy. Ziegler and coworkers have described a GIAO-DFT method (71) that is available as part of the Amsterdam density functional package (72). An alternate method developed by Cheeseman and co-workers (73) is implemented in Gaussian 94 (74). 

C. Fonseca Guerra, O. Visser, J. G. Snijders, G. te Velde, and E. J. Baerends, in Methods and Techniques for Computational Chemistry, E. Clementi and G. Corongiu, Eds., STEF, Cagliari, Italy, 1995, pp. 305-395, and references therein. Parallelisation of the Amsterdam Density Functional Program. 

Valence bond (VB) theory may be used as an alternative to molecular orbital (MO) theory for computational organotin studies. Most MO calculations of organotin systems use Gaussian, GAMESS, or Amsterdam density functional (ADE) program suites. A variety of VB methods exist, and although VB wavefunctions are more difficult to calculate, some VB methods can also be implemented in these programs. ... 

FIGURE 8.5 Reaction coordinates for formation of adsorbed ethylene oxide (EO ) (a and b) and adsorbed acetaldehyde (ACE ) (c and d) formation using both DACAPO (a and c) and Amsterdam Density Functional (ADF) (b and d). The activation energies are quite similar in both methods. 

The Amsterdam Density Functional (ADF) method [118,119] was used for calculations of some transactinide compounds. In a modem version of the method, the Hamiltonian contains relativistic corrections already in the zeroth order and is called the zero-order regular approximation (ZORA) [120]. Recently, the spin-orbit operator was included in the ZORA Fock operator [121]. The ZORA method uses analytical basis fimctions, and gives reliable geometries and bonding descriptions. For elements with a very large SO splitting, like 114, ZORA can deviate from the 4-component DFT results due to an improper description of the pi/2 spinors [117]. Another one-component quasirelativistic scheme [122] applied to the calculations of dimers of elements 111 and 114[116,117]isa modification of the ZORA method. 

In the present study, we aim to analyze Raman and valence X-ray photoelectron spectra of chitosan film with Kr+ ion beam irradiation. We performed quantum chemical calculations to simulate the experimental Raman and valence X-ray photoelectron spectra (XPS) of the Kr+ ion-irradiated film at B3LYP/6-31G(d, p) level by GAUSSIAN 09 software [5] and with the statistical average of orbital potential (SAOP) method [6] of Amsterdam density functional (ADF) program [7], respectively. 

The Amsterdam Density Functional package (ADF) is software for first-principles electronic structure calculations (quantum chemistry). ADF is often used in the research areas of catalysis, inorganic and heavy-element chemistry, biochemistry, and various types of spectroscopy. ADF is based on density functional theory (DFT) (see Chapter 2.39), which has dominated quantum chemistry applications since the early 1990s. DFT gives superior accuracy to Hartree-Fock theory and semi-empirical approaches, especially for transition-metal compounds. In contrast to conventional correlated post-Hartree-Fock methods, it enables accurate treatment of systems with several hundreds of atoms (or several thousands with QM/MM)." ... 

We will start with a description of FDE and its ability to generate diabats and to compute Hamiltonian matrix elements—the EDE-ET method (ET stands for Electron Transfer). In the subsequent section, we will present specific examples of FDE-ET computations to provide the reader with a comprehensive view of the performance and applicability of FDE-ET. After FDE has been treated, four additional methods to generate diabatic states are presented in order of accuracy CDFT, EODFT, AOM, and Pathways. In order to output a comprehensive presentation, we also describe those methods in which wavefunctions methods can be used, in particular GMH and other adiabatic-to-diabatic diabatization methods. Finally, we provide the reader with a protocol for running FDE-ET calculations with the only available implementation of the method in the Amsterdam Density Functional software [51]. In closing, we outline our concluding remarks and our vision of what the future holds for the field of computational chemistry applyed to electron transfer. 

All the calculations were carried out using the Amsterdam Density Functional (ADF) code, Version 2.3 (Theoretical Chemistry, Vrije Universiteit, Amsterdam, The Netherlands), developed by Baerends et al. (41), which incorporates the relativistic extensions first proposed by Snijders et al. (42). The code was vectorized by Ravenek (43) and parallelized by Fonseca Guerra et al. (44), and the numerical integration scheme applied for the calculations was developed by te Velde et al. (45). The ADF method utilizes Slater-type orbitals (STOs) for basis functions. 

In parallel, the classical FD procedure of Bashford and Karplus has been coupled with the Amsterdam density functional theory (DFT) code to give another version of QM-FD methods. Starting from a DFT calculation in vacuo, the RF potential is obtained as the difference between the solutions of the Poisson equation obtained with an FD method in the medium and in vacuo (in both cases the electrostatic potential is expressed in terms of PD atomic charges). The RF potential is then recomputed to solve a modified Kohn-Sham equation. The calculations are repeated until convergence is achieved. 

Jursic, B. S., 1996, Computing Transition State Structures With Density Functional Theory Methods in Recent Developments and Applications of Modem Density Functional Theory, Seminario, J. M. (ed.), Elsevier, Amsterdam. 

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