Magnetic circular dichroism spectra from resonant and damped coupled cluster response theory

A computational expression for the Faraday A term of magnetic circular dichroism (MCD) is derived within coupled cluster response theory and alternative computational expressions for the B term are discussed. Moreover, an approach to compute the (temperature-independent) MCD ellipticity in the context of coupled cluster damped response is presented, and its equivalence with the stick-spectrum approach in the limit of infinite lifetimes is demonstrated. The damped response approach has advantages for molecular systems or spectral ranges with a high density of states. Illustrative results are reported at the coupled cluster singles and doubles level and compared to time-dependent density functional theory results.Comment: Submitted to J. Chem. Phys. on May 10, 202

Structures and harmonic vibrational frequencies for excited states of diatomic molecules with CCSD(R12) and CCSD(F12) models

The equation-of-motion coupled-cluster method for excited states with the singles-and-doubles model (CCSD) has been implemented for ansatz 2 of the explicitly correlated CCSD(R12) and CCSD(F12) methods as part of the program package Dalton. In this model, an orthonormal complementary auxiliary basis set is used for the resolution-of-identity approximation in order to calculate the three-electron integrals needed for CCSD(R12) and CCSD(F12). The additional CCSD(R12) or CCSD(F12) terms introduced within ansatz 2, which are not present in ansatz 1, are derived and discussed with regard to the extra costs needed for their computation. As a first application the basis set convergence of equilibrium bond lengths and harmonic vibrational frequencies has been investigated for some singlet excited states of the diatomic molecules N2, CO, BF, and BH. The calculated CCSD(F12) results show that the average absolute deviations of the bond lengths and frequencies from the basis set limits are below 0.1 pm and 5 cm-1 as well as 0.05 pm and 1 cm-1 for the triple- and quadruple- basis sets, respectively. These deviations are shown to largely arise from the SCF basis set incompleteness errors. © 2009 American Institute of Physics.published_or_final_versio

Highly accurate CCSD(R12) and CCSD(F12) optical response properties using standard triple-ζ basis sets

Coupled-cluster response theory for frequency-dependent optical properties within the coupled-cluster singles-and-doubles model (CCSD) has been derived and implemented for ansatz 2 of the explicitly correlated CCSD(R12) and CCSD(F12) methods as part of the program package DALTON. The basis set convergence of static dipole moments, polarizabilities, and parallel averages of first and second hyperpolarizabilities has been investigated for Ne, BH, N2, CO, and BF. The frequency-dependent results are presented for the electronic second-harmonic generation of N2. With triple-ζ basis sets, the CCSD(F12) correlation contributions using ansatz 2 are close to the basis set limits for dipole moments and second hyperpolarizabilities; the CCSD(R12) results are better than the CCSD results obtained with at least quintuple- ζ basis sets for polarizabilities and first hyperpolarizabilities. The exponent of Slater-type correlation factor for CCSD(F12) ground state energy may not be optimal and has to be re-examined for response properties. We also suggest that the remaining one-electron basis set errors arising within the coupled-cluster singles should be reduced by allowing excitations into the auxiliary orbital space. © 2009 American Institute of Physics.published_or_final_versio

Log del Pezzo C∗\mathbb{C}^*-surfaces, K\"ahler-Einstein metrics, K\"ahler-Ricci solitons and Sasaki-Einstein metrics

We consider two classes of non-toric log del Pezzo $\mathbb{C}^*$-surfaces: on the one side the 1/3-log canonical ones and on the other side those of Picard number one and Gorenstein index at most 65. In each of the two classes we figure out the surfaces admitting a K\"ahler-Einstein metric, a K\"ahler-Ricci soliton and those allowing a Sasaki-Einstein metric on the link of their anticanonical cone. We encounter examples that admit a K\"{a}hler-Ricci soliton but no Sasaki-Einstein cone link metric.Comment: 27 page

Damped (linear) response theory within the resolution-of-identity coupled cluster singles and approximate doubles (RI-CC2) method

An implementation of a complex solver for the solution of the response equations required to compute the complex response functions of damped response theory is presented for the resolution-of-identity (RI) coupled-cluster singles and approximate doubles CC2 method. The implementation uses a partitioned formulation that avoids the storage of double excitation amplitudes to make it applicable to large molecules. The solver is the keystone element for the development of the damped coupled-cluster response formalism for linear and nonlinear effects in resonant frequency regions at the RI-CC2 level of theory. Illustrative results are reported for the one-photon absorption cross section of C60, the electronic circular dichroism of $n$-helicenes ($n$ = 5, 6, 7), and the $C_6$ dispersion coefficients of a set of selected organic molecules and fullerenes.Comment: Submitted to J. Chem. Phys., Dec. 202

Lattice Polygons and Surfaces with Torus Action

This thesis contributes to the classification of log del Pezzo surfaces with torus action. Such a surface is 1/k-log canonical if all discrepancies of a resolution of singularities are greater than or equal to -1+1/k. We present an explicit classification strategy for fixed k as well as the concrete results in the cases k=1,2,3. [untranslated

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Fachangestellte für Medien- und Informationsdienste / Fachrichtung Bibliothek

Seit September 2006 bilden wir an der Bibliothek der Universität Konstanz Fachangestellte für Medien- und Informationsdienste, Fachrichtung Bibliothek aus. Uns stehen zwei Ausbildungsplätze zur Verfügung, und wir wechseln uns mit den anderen wissenschaftlichen Bibliotheken des Landes Baden-Württemberg ab, so dass wir alle zwei Jahre mit einem neuen Ausbildungsjahrgang beginnen