Davide Cianchino

Davide Cianchino

Doktorand

Geb. B2.2    Raum 2.14
Tel.: +49-(0)681 302 3858
davide.cianchino(at)uni-saarland.de

Computational chemistry is a fundamental tool to help studying, understanding, and rationalizing chemical reactivity. By identifying stable intermediates, transition states, and reaction coordinates, it acts as a powerful microscope, offering a molecular perspective into the reaction.
Modeling chemical reactivity, from a theoretical (and computational) point of view, means to characterize the minima as well as the saddle points of the molecular potential energy surface (PES); the main tool to accomplish this task is the calculation of vibrational frequencies, using analytical second derivatives of the energy (Hessian) with respect to the coordinates, that are used both to confirm the nature of the critical points of the PES and to compute thermal corrections to the molecular energies. A major bottleneck in the calculation of the Hessian for large molecular systems is the evaluation of the electron-repulsion integrals. Nonetheless, in recent years very efficient implementations have been proposed to tackle this problem, and in particular in this project we make use of the Cholesky Decomposition technique. The aim of this project is therefore to formulate, derive, and implement a general CD-based strategy for geometrical second derivatives, and to deploy it for post-Hartree Fock methods (either CASSCF or Coupled-Cluster) for modeling chemical reactions. An additional challenge will be to extend the implementations for the complex case, in order to study how a strong magnetic field affects the reaction mechanism.