Virpesinės spektrometrijos ir matricinės izoliacijos metodo taikymas molekulių su Silicio pakaitais struktūros tyrimams /

The work aims to determine the structure and stability of the newly synthesized molecule Si_3 O_2 Cl_8 by applying vibrational spectrometry methods and determine the number of possible conformers. To determine the number of conformers, the Raman scattering spectrum was recorded. Secondly, the infrared absorption spectrum at room temperature - 294.15 K was recorded. Due to the overly broad spectral bands and the significant influence of the environment, it is impossible to evaluate conformational distribution from these data. In order to overcome these limitations molecule was isolated in inert media at low temperature and infrared absorption spectra recorded. Three different environments were employed, namely argon, neon, and nitrogen gases. The obtained experimental data show a complex band structure from which we cannot conclude whether one or two conformers are present. To determine the number of possible conformers, temperature experiments were conducted. Theoretical calculations were performed using HPC “Saulėtekis”, utilizing Gaussian 16 software as well to facilitate interpretation of the spectra. The method employed was M06-2x (DFT), with a cc-pVTZ basis set. From the obtained spectra, it can be concluded that the molecule is unstable in the gas phase and ambient conditions. When the molecule is kept in a gaseous state for a long time, it decomposes upon interaction with the water vapour or with water molecules on surfaces. The decomposition products include HCl, molecule, another component low vapor pressure compound and is not detected matrices. Additionally, after conducting an experiment where the sample was rapidly mixed with inert gases, the results indicated that the molecule is stable and does not undergo decomposition. Based on theoretical calculations, it was determined that two conformers could potentially exist with similar energies. However, upon analyzing the infrared absorption spectra, it was found that only one conformation exists in the sample. The presence of a single conformer is explained by the fact that during the preparation of the sample, the molecule rapidly relaxes to the lowest energy conformation, which is then trapped in the matrix.

Grantor dc:publisher

Institutional Repository of Vilnius University

Year dc:date

2024

Author dc:creator

• Pukalskaitė, Klaudija,

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

lit

Repository record dc:identifier

https://repository.vu.lt/VU:ELABAETD210577759&prefLang=en_US

OAI identifier oai:identifier

oai:vu.lt:elaba:210577759