1. Jens Martensson Sulfonamides were the first antibiotic drugs used in the treatment of bacterial diseases in humans. Sulfonamides have the general formula RSO 2 NH 2, where R is a certain organic group. For example, "methanesulfonamide" is CH 3 SO 2 NH 2. Any sulfonamide can be assumed to be derived from sulfonic acid by replacing an amine group with a hydroxyl group. 1 Introduction

2. Jens Martensson 2 The chemical composition of some medicines (Zhang 2018) ÇANKIRI 2021

3. Jens Martensson 3  In this thesis study, first of all, the structure of S2M-S3, S2M-S3(Cu) and S2M-S3(Pd) compounds synthesized by Saliha ALYAR for the first time we will optimize with DFT/B3LYP/6-311++G (d, p) theoretical level and lowest energy stable structures will be obtained. ÇANKIRI 2021  The vibrational frequencies of these compounds, H and C NMR calculations, will be made with the same basis set in the DMSO phase and compared with the experimental data.  Finally, HOMO and LUMO molecular orbital energies, nonlinear optical properties (NLO) and molecular electrostatic potential (MESP) maps will be examined at the DFT/B3LYP/6-311++G (d, p) theory level. The theoretical results obtained from the calculations will be interpreted by comparing them with the existing experimental values.

4. Jens Martensson 4 ÇANKIRI 2021 Electromagnetic waves

5. Jens Martensson Electromagnetic waves emitted from a point source (such as a light bulb) have a sphere as their wavefront. The electromagnetic wave's wavelength can be used to describe the location of the electromagnetic wave within the electromagnetic spectrum. Since electromagnetic waves of different frequencies have different sources and effects on matter, different names are given. In order to increase the frequency and decrease the wavelength, the following are indicated: Electromagnetic radiation is an example of radio waves, microwaves, infrared radiation, visible light, x-rays and gamma rays. 5

6. Jens Martensson 6

7. Spectroscopy 7  Spectroscopy is an accurate color analysis as it refers to all electromagnetic spectrum bands, including visible light. Indeed, spectroscopy started as a study of the wavelength dependence of visible light dispersed through a prism emission of gas phase matter. Matter waves and acoustic waves are also examples of radiant energy.  Spectroscopy is divided into two parts: Atomic and Molecular Spectroscopy. Atomic spectroscopy is based on the absorption, emission and fluorescence properties of gaseous atoms or monatomic ions. Molecular spectroscopy focuses on molecular absorption, emission and reflection.

8. Jens Martensson 8 Spectroscopic methods Ultraviolet– visible spectroscopy Atomic absorption spectroscopy Nuclear magnetic resonance spectroscopy Mass spectrometry X-ray spectroscopy Gamma Ray Spectroscopy Raman spectroscopy Infrared Spectroscopy

9. Jens Martensson 9 MOLECULAR VIBRATION TYPES It is very easy to measure the shape and number of vibrations in the basic diatomic or triatomic molecule and infer their relationship to the energy absorbed. These dimensions are complex for polyatomic molecules; In these centers there are many centers of vibration as well as various links between them.

10. Jens Martensson 10 There are described four distinct vibration forms:  Stress (stretching) vibrations ()  Bending vibrations ()  Out of plane bending ()  Torsion vibration ( )

11. Jens Martensson 11 MOLECULAR MODELING WITH QUANTUM MECHANICAL METHODS  Effective techniques are needed in order to better understand quantum multi- body physical systems beyond the medium-field paradigm and to investigate the behaviour of highly correlated electrons.  In quantum mechanical methods, the structure and properties of the molecule are determined by the laws of quantum mechanics. ÇANKIRI 2021  While the number of particles often increases exponentially in the Hilbert system's space.

12. Jens Martensson 12 * SELF consistent field methods are Density Functional Theory (DFT) and Hartree Fock (HF). The main challenge faced by both methods is, it is the molecular integrals that appear in the solution of the Schrödinger equation. * It is very difficult and time consuming to solve these integrals, so their cost is high. Electron- electron interactions are based on an average potential. * DFT process, as a function of electron density, calculates the energy of molecular systems. Electron It provides very good results in molecular properties because it takes into account their correlations. ÇANKIRI 2021

13. Jens Martensson 13 Quantum mechanics equation of motion: Schrödinger Equation By solving the Schrodinger equation, the energy and many properties of a system can be found: For hydrogen and related atoms, the Hamiltonian expression : The Hamiltonian expression of a molecule in atomic units:

14. Jens Martensson Born - Oppenheimer Approach 14 Born - The approach to Oppenheimer is an approach used to facilitate the Schrödinger equation solution. The mass of the nuclei is much greater than the mass of electrons, and electrons move faster than the nucleus, according to this approach. In the Hamiltonian expression given to zero, the kinetic energy terms of the nuclei, the term representing the repulsive potential between nuclei, will be equal to a constant because the distance between nuclei is assumed to be constant. So the multi-electron system's Hamiltonian expression. ÇANKIRI 2021

15. Jens Martensson 15 Slater determinant The wave function describing a system with N electrons is given by the Slater determinant. Since electrons are fermions, both the Pauli principle and the antisymmetric wave function property are given by this determinant. ÇANKIRI 2021

16. Jens Martensson Charts and Graphs 1 16 Variation method Method of variance, which offers a means to measure the energies of the ground state and wave structure of complex systems. According to the variety process. it is given by ÇANKIRI 2021

17. Jens Martensson 17 ÇANKIRI 2021 Hartree - fock method self consistent field (SCF) theory Fock and Slater developed the Schrödinger equation for multi-electron systems using the Self-consistent field method (SCF) variance method found by Hartree Later to incorporate electron exchange methods. Each electron moves within the mean spherical potential caused by other electrons The Hamiltonian processor of a system with N electrons and the wave function for a system with N electrons If substituted in the equation of variation given by the Hamiltonian and the wave function.

18. Jens Martensson An expression of energy is obtained: 18  - This definition encompasses three kinds of integrals, an electron integral defined by the function of the V wave provides the average value of the electron's kinetic energy and its contact with the nucleus.  - Second integral, it is called the Coulomb integral. The condensation of the charge distributions of two electrons is indicated by this integral.  - The last integral is called the exchange integral The presence of the exchange integral depends on the same spin states of the electrons. This integral is the identity and representation of electrons by antisymmetric wave functions. ÇANKIRI 2021

19. Jens Martensson 19 Density functional theory (DFT) The functional theory of density (DFT) expresses the system's energy as a function of electron density. This approach covers the process of solving an electron density- based variance equation. Considering the correlations of all electrons belonging to the molecular structure of the DFT, the effects of association and correlation are therefore taken into account. This approach owes its thinking to the principle of Hohenberg-Kohn. ÇANKIRI 2021

20. Jens Martensson 20  The first theorem of Hohenberg-Kohn notes that there is a way of measuring molecular properties from the density of electrons.  The second principle of Hohenberg - Kohn states that it is possible to measure the energy and electron density using a variational method. Density of Electrons, ÇANKIRI 2021

21. Jens Martensson 21 Potential energy surface (PES) The surface of potential energy (PES) is a multidimensional surface that determines the molecule's energy as a function of atomic coordinates. A molecule's form or three-dimensional structure is frequently described using the term "contour." Each point on the surface corresponds to a different configuration of the molecule. Different shapes of the molecule, it can be obtained by changing the molecular parameters: ÇANKIRI 2021 bond length, bond angle, torsion angle

22. Jens Martensson 22 If rotations around single bonds are considered as parameters, there may be multiple minimum and maximum points on the potential energy surface For a specific region on the potential energy surface, the lowest local energy state minimum, the region with the lowest energy on the entire potential energy surface, is called the global minimum. ÇANKIRI 2021

23. Jens Martensson 23 Geometry optimization Optimization is called the process of finding the stable points of a function. Most optimization algorithms also calculate or estimate the Hessian matrix, known as the power constants matrix. Force constants describe the curvature of the surface at this point, which helps determine the next stage. ÇANKIRI 2021 Geometry optimization is called the process of finding the minimum energy point and molecular coordinates on the PES.