# Computational Chemistry

## Objectives

The curricular unit aims to give the student an introductory formation in the field of Computational Chemistry, mainly applied in the modeling of organic structures. It is hopped that the student gets knowledge and skills that allow him to select and use the best theoretical models, from the large number of available possibilities, in the resolution of real problems in organic chemistry, both from the thermodynamic and the kinetic point of views.

## General characterization

##### Code

10705

##### Credits

3.0

##### Responsible teacher

António Gil de Oliveira Santos

##### Hours

Weekly - 2

Total - 29

##### Teaching language

Português

### Prerequisites

The students should have good knowledge of Organic and Physical Chemistry, and basic knowledge of Mathematics.

### Bibliography

2. Molecular Modelling, Principles and Applications, Andrew R. Leach, 2nd Ed., Pearson, Prentice Hall, 2001.

3. Introduction to Computational Chemistry, Frank Jensen, John Wiley and Sons, 1999.

### Teaching method

The classes use modern multimedia techniques. The students have access to classrooms equipped with desktop computers, with software for 3D modeling and visualization, as well as to the computer cluster working in the Chemistry Department.

### Evaluation method

The students are evaluated by one individual quizz that includes 50% of practical questions and 50% of theoretical questions.

## Subject matter

Thermodynamic and kinetic concepts: Potential energy surfaces (PES). Maximums, local and global minimums in the PES. Reagents, intermediates, transition states, and products of chemical reactions. Localization in the PES. Mathematical conditions for the identification of each state in the PES. Molecular mechanics. Mathematical formalist of the models based on Classical Mechanics. Common used force-fields. Application in real problems. Electronic models. Approximations to solutions of the Schödinger’s equation. Ab-initio models. Hartree-Fock theory (molecular orbital theory). Born-Hoppenheimer approximation. Hartree-Fock approximation. LCAO approximation (linear combination of atomic orbitals). Mathematical implementation of the three approximations. The Slater determinant. Equations of Roothaan-Hall. Variational principle. Optimization of molecular wave-functions. Optimization of structures. Frequency calculation. Thermodynamic parameters. Calculation of transition state structures. Basis sets. Semi-empirical models. Post-HF models. Electronic correlation. Short introduction to the theory of Moller-Plesset (MP) and to the configuration interaction theory (CI). Short introduction to the density functional theory (DFT).