Sat , Apr 22 9 : 30 0 : 45

not available. Sat, Apr 22 10:15 0:35 Tom Ziegler The application of TDDFT to systems with a spin or space degenerate ground state Tom Ziegler, Mike Seth, and Fan Wang. Department of Chemistry, University of Calgary University Drive 2500, University of Calgary, 2500 University Drive, Calgary, AB T2N 1N4, Canada Ordinary time-dependent density functional theory (TDDFT) is not able to treat single excitations involving spin-flips and can thus not treat systems with spin generate ground state. We introduce in the first part of our talk a formulation of TDDFT based on a noncollinear representation of the XC potential. Within the noncollinear representation, we are able to apply TDDFT to atoms and molecules with a spin-degenerate ground state and thus study spinmultiplet splittings. The second part of the talk deals with spatially degenerate ground states using time-dependent density functional theory (TDDFT). We propose here a new “Transformed reference via an intermediate configuration Kohn-Sham TDDFT (TRICKSTDDFT) method. This method avoids the complications caused by the multi-reference nature of spatially degenerate ground state by taking a non-degenerate excited state with desirable properties as the reference for the TDDFT calculation. The scope and practical application of the method is discussed. Sat, Apr 22 11:05 0:45 Alberto Vela The Lieb-Oxford bound and the large gradient limit in the exchange-correlation energy Abstract not available. Sat, Apr 22 11:50 0:25 Mark E. CASIDAnot available. Sat, Apr 22 11:50 0:25 Mark E. CASIDA Progress on TDDFT in deMon2k Abstract not available.not available. Sat, Apr 22 12:15 0:25 Mike Seth The Calculation of MCD Spectra with TDDFT Department of Chemistry, University of Calgary University Drive 2500, University of Calgary, 2500 University Drive, Calgary, AB T2N 1N4, Canada Magnetic Circular Dichroism (MCD) is defined as the difference in absorption intensity of left and right circularly polarized light in the presence of a magnetic field. If the MCD as a function of the energy of the incident light is measured then an MCD spectrum is obtained. MCD spectroscopy has been shown to be capable of providing much useful information including insight into the symmetry, the structure and the magnetic moment of the molecule of interest and also can aid in the assignment of the corresponding absorption spectrum. In more recent applications, the selectivity of MCD has been utilized in studies of complicated systems such as enzymes. In the last few years we have been working on methods of calculating MCD spectra using time-dependent density functional theory. This talk will summarize our progress so far. MCD can be shown to arise due to several different contributions, each with its own physical origin. We have considered the MCD that appears when degenerate excited states are split by the applied magnetic field (A terms) and the MCD caused by breaking the degeneracy of the ground state (C terms). The calculation of C terms further required the ability to perform TDDFT calculations on systems with a degenerate ground state. Finally, it has been shown that spin-orbit coupling introduces further contributions to the MCD that can dominate the spectra when the system has little symmetry or a ground state that is only spin degenerate. Our most recent work deals with calculating these spin-orbit contributions. Sat, Apr 22 16:30 0:35 Florian Janetzko Ab initio CCM: Inclusion of long-range interactions Florian Janetzko and Andreas M. Köster Departamento de Química, CINVESTAV, Avenida Instituto Politécnico Nacional 2508, A.P. 14-740 México D.F. 07000, México The SCF behavior of Cyclic Cluster Model (CCM) calculations within the deMon2k code is analyzed. The imposing of periodic boundary conditions by the CCM introduces fictitious orbitals and auxiliary functions, which cause problems for the transformation of the Kohn-Sham matrix into the orthogonal basis and the variational fitting of the Coulomb potential. A solution to these problems is (a) the use of a canonical orthogonalization of the Kohn-Sham matrix and (b) the transformation of the fitting equation into the diagonal basis of the auxiliary functions. It is shown that these modifications considerably improve the stability of the SCF in molecular calculations, too. Finally, the Cyclic Cluster formalism for ab initio Kohn-Sham DFT is derived from the full periodic ansatz and the inclusion of the long-range interactions is presented. Sat, Apr 22 17:05 0:25 Hongjuan Zhu A Theoretical Study of the Original Shilov Reaction Involving Methane Activation by Platinum Tetrachloride (PtCl4 2) in an Acidic Aqueous Solution Hongjuan Zhu and Tom Ziegler Department of Chemistry, University of Calgary, 2500 University Drive, N.W. Calgary, Alberta, Canada T2N 1N4 Density functional theory (DFT) has been employed to investigate the rate-determining step for the Shilov reaction in which PtCl4 2can catalyze H-D exchange of alkanes in acidic aqueous solution. C-H activation and methane uptake are the two possible candidates. Associative and dissociative pathways are both considered in the methane uptake step. It was not possible to determine whether methane uptake followed an associative or dissociative mechanism due to uncertainties in the calculated contributions to the free energy of activation from entropy and solvation. The active species in the Shilov reaction are PtCl4 2, PtCl3H2O and PtCl2(H2O)2. We have shown that PtCl2(H2O)2 is the most active catalyst for H/D exchange. Rate expressions for the Shilov reaction have been derived for different reaction conditions. Sat, Apr 22 17:30 0:25 Jorge Martín del Campo Ramírez Structure Optimization with Levenberg-Marquardt Methods Jorge Martín del Campo Ramírez and Andreas M. Köster Departamento de Química, Centro de Investigación y Estudios Avanzados del I.P.N., Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, México D.F. 07360 Restricted step methods are widely used for molecular structure optimizations. In this presentation we show the implementation of a restricted step method based on the Levenberg-Marquardt step selection [1]. We will demonstrate that this step selection is superior to the RFO algorithm [2] currently implemented in deMon2k. We will also derive the extension of the LevenbergMarquardt step selection for a potential energy walking algorithm as well as for the transition state search [3]. The relation to the intrinsic reaction coordinate algorithm from Schlegel [4] is worked out. Selected examples are presented. References [1] K. Levenberg, Quart. Appl. Math. 2, 164 (1944). D. W. Marquardt, SIAM J. 11, 431 (1963). R. Fletcher, Practical Methods of Opimization, Vol. 1 (John Wiley and Sons, Salisbury, 1980). [2] A. Banerjee, N. Adams, J. Simons, R. Sherpard, J. Phys. Chem. 89, 52 (1985). J. Baker, J. Comp. Chem. 7, 385 (1986). [3] P. Culot, G. Dive, V. H. Nguyen, J. M. Ghuysen, Theor. Chim. Acta. 82, 189 (1992). J. M. Bofill, J. Comp. Chem. 15, 1 (1994). [4] C. Gonzalez, H. B. Schlegel, J. Phys. Chem. 94, 5523 (1990). Sat, Apr 22 17:55 0:25 Alicija Haras DFT Study on the Copolymerization of Ethylene with Polar Monomers Catalyzed by Transition Metal Complexes A. Haras a , G. D. W. Anderson, A. Michalak a,b , B. Rieger c , T. Ziegler a a Department of Chemistry, University of Calgary, University Drive 2500, Calgary, Alberta, Canada T2N 1N4 b Department of Theoretical Chemistry, Jagiellonian University, R. Ingardena 3, 30-060 Cracow, Poland c Department of Inorganic Chemistry II “Material Science & Catalysis, University of Ulm, 89081 Ulm, Germany DFT method is well proven to be valuable tool in analyzing compounds containing transition metal atoms. Herein we present our theoretical study on the copolymerization of ethylene with polar monomers in the presence of the neutral Pd(II) complexes proposed by Drent et al. [CHEM. COMMUN. 2002, 744–745]. Based on experimental findings by the authors, the catalytic systems are capable to provide a linear topology of copolymers composed of ethylene and methacrylate but the origins of this phenomenon remain unclear. Our computational data on processes involved in chain propagation and migration of catalytic active center along the formed polymer chain allow to rationalize the experimentally observed behavior of the Drent systems and to propose some modifications of the catalyst in order to obtain its higher efficiency. Sun, Apr 23 9:00 0:35 Tomasz A. Wesolowski Subsystem formulation of DFT: Recent formal developments and applications of the orbital-free embedding formalism -deMon2K