Density functional theoiy

An impressive application of infrared and Raman spectroscopy was demonstrated in studies of superelectrophilic diprotonated thiourea, [H3NGSH jNfE 2+ 2AsFf,. The Raman spectrum (taken at — 110°C) corresponded reasonably well with calculated vibrational bands predicted by density functional theoiy.38 Coupled with computational methods for predicting vibrational frequencies, it is expected that vibrational spectroscopic techniques will be useful for the observations of these and other superelectrophiles. 

Quantum mechanics provide many approaches to the description of molecular structure, namely valence bond (VB) theoiy (S-70), molecular orbital (MO) theoiy (11,12), and density functional theoiy (DFT) (13). The former two theories were developed at about the same time, but diverged as competing methods for describing the electronic structure of chemical systems (14). The MO-based methods of calculation have enjoyed great popularity, mainly due to the availability of efficient computer codes. Together with geometiy optimization routines for minima and transition states, the MO methods (DFT included) have become prevalent in applications to molecular structure and reactivity. 

Saielli, G. Nicolaou, K. C. Ortiz, A. Zhang, H. Bagno, A. Addressing the stoeo-chemistry of complex organic molecules by density functional theoiy-NMR vamiusal B in retrospective, 7. Am. Chem. Soc. 2011,133, 6072-6077. 

Grimme, S. n-Alkane isodesmic reaction enagy errors in density functional theoiy are due to electron correlation effects, Org. Lett. 2010,12,4670-4673. 

Lastoskie, C.M., Gubbins, K.E. and Quiike, N.J., Pore size distribution analysis of microporous carbons a density functional theory approach. J. Phys. Chem. 97 (1993) 4786. Olivier, J.P., Modeling physical adsorption on porous and nonporous solids using density functional theoiy. J. Porous Materials 2 (1995) 9. 

Electronic absoiption and emission spectra of Au cluster have been calculated using time-dependent density functional theoiy (TD-DFT). The calculations predict a large Stokes shift for Aug cluster. It has been shown that the calculated absorption spectrum is in good agreement with the experimental data. 

Kohn-Sham Time-Dependent Density Functional Theoiy... 

In the density functional theoiy (DFT) the statistical mechanical grand canonical ensemble is utilized. The appropriate free energy quantity is the grand Helmholtz free energy, or grand potential functional, 2(r. This free energy functional is expressed in terms of the density... 

Berccs, A., Ziegler, T. Application of Density Functional Theoiy to the Calculation of Force Fields and Vibrational Frequencies of Transition Metal Complexes. 182, 41-85 (1996). 

Dobson, J, F. Density Functional Theoiy ofTime-Dependent Phenomena I81,81-172 (1996) Dohm, J., VOgtle, F. Synthesis of (Strained) Macrocycles by Sulfone Pyrolysis. 161,69-106 (1991). 

Edelmann, F.T. Rare Earth Complexes with Heteroallylic Ligands. 179, 113-148 (1996). Edelmann, F.T. Lanthanide Metallocenes in Homogeneous Catalysis.7 79, 247-276(1996). El-Basil, S. Caterpillar (Gutman) Trees in Chemical Graph Theory. 753, 273-290 (1990). Engel, E. Relativistic Density Functional Theoiy.757, 1-80 (1996)... 

Fronzoni G, Stener M, Decleva P, Wang F, Ziegler T, Van Lenthe E, Baerends E (2005) Spin-orbit relativistic time dependent density functional theoiy calculations for the description of core election excitations TiCL, case study. Chem Phys Lett 416 56-63... 

Oliphant N, Bartlett RJ (1994) A systematic comparison of molecular properties obtained using Hartiee-Fock, a hybrid Hartiee-Fock density functional theoiy, and coupled-cluster methods. J Chem Phys 100 6550-6561... 

De Luca G, Russo N, Koster AM, Calaminici P, Jug K (1999) Density functional theoiy calculations of nuclear quadrapole couphng constants with cahbrated 0 quadrapole moments. Molec Phys 97 347-... 

A wave funetion-based method, second-order Moller-Plesset (MP2) perturbation theory, is usually considered to be the high-level approach, and could yield reliable results for the weak interactions. However, the MP2 method needs mueh more computational cost, and cannot be applied to large systems. Henee, an alternative method, density function theoiy (DFT), including PW91, B3LYP, and PBE, has been developed and widely used. In addition, the basis set superposition (BSSE) is critically necessary to describe... 

Density Functional Theoiy Model of Adsorption on Amorphous and Microporons 9 Solids... 

The synthesis (Scheme 12.8) of the first [l2]collarene molecular belt (12.18b) was achieved in our laboratory through the repeated application of Diels-Alder (DA) cycloadditions between the dienophile 12.20 and the diene 12.21, which proceeds with extraordinarily high diastereoselectivity. While the DA reaction between 12.20 and 12.21 could, potentially, lead to four different diastereoisomeric products, only a single diastereoisomer was actually observed in this reaction. This especially high diastereoselectivity is dictated primarily by electronic effects, which kinetically favor attack on the diene 12.21 from the endo face, while attack on the dieneophile 12.20 is preferred from the exo side. Density functional theoiy (DFT) calculations (Figure 12.7) reveal that the observed diastereoselectivity has its cause in the selective stabilization of the endo-exo transition state (12.19a). 

Based on the non local density functional theoiy (NLDFT) pore analysis, the pore size distributions for slit shaped pores were deduced fiom the N2 adsorption isotherms. 

In the Time Dependent Density Functional Theoiy (TDDFT) [16], the correlated many-electron problem is mapped into a set of eoupled Schrodinger equations for each single electronic wavefunctions (stj r,i),j=, n), which yields the so-called Kohn-Sham equations (in atomic units)... 

Ohkubo et study electronic properties structure and transport coefficients (conductivity and self-diffusion) of a molten acLi20-(1 — x)B203 system using first-principles MD simulations performed with their own finite element density functional theoiy code, FEMTECK and PFG NMR measurements. For diffusion the first-principles simulation results were in better agreement with experiment than that obtained from classical simulations. 

G. Cipriani, D. Loffreda, A. Dal Corso, S. de Gironcoli, S. Baroni, Adsorption of atomic oxygen on Ag(001) a study based on density-functional theoiy. Surf. Sci. 501(3), 182-190 (2002)... 

The density functional theoiy (DFT) was mentioned previously in Chapter 4, and the Thomas-Fermi method can also be viewed as a special case of DFT. DFT has become very popular over the last 20 years or so. The reasons are obvious — it scales as where N is the number of electrons—by contrast to standard ab initio Hartree-Fock theory, which scales as N, and the results are more accurate (not to mention accurate ab initio theories, which scale as N ). Furthermore the DFT theory operates in three dimensions (x, y, z) in which the electron density is defined—no matter how many electrons are involved. DFT theory has been reviewed and described in numerous books and review articles see, for instance, [212]. We shall therefore only give a brief presentation of it here. 

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