Interaction in metal rare gas complexes and assignment of REMPI spectra of some disubstituted benzenes

Zheng, Yu (2018) Interaction in metal rare gas complexes and assignment of REMPI spectra of some disubstituted benzenes. MSc(Res) thesis, University of Nottingham.

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Abstract

A consistent set of interaction energy curves are shown in this work for the Group 2 (IIA) and Group 12 (IIB) metal cation/rare gas complexes, M+ RG, where M+ = Be+–Ra+ and Zn+–Hg+; and RG = He–Rn. spectroscopic constants derived from these are reported and compared with available data, and discuss trends in the values. Insight into the interactions are gained that occur using a range of approaches: reduced potential energy curves; charge and population analyses; molecular orbital diagrams and contour plots; and Birge-Sponer plots. Although sp hybridisation occurs in the Be+ RG, Mg+ Rg and Group 12 M+ RG complexes, this appears to be minimal and covalency is the main aspect of the interaction. However, major sd hybridisation occurs in the heavier Group 2 M+ RG systems, which increases their interaction energies but there is minimal covalency. Examination of Birge-Sponer plots reveals significant curvature in many cases, which are ascribed to the changing amounts of hybridisation or covalency as a function of internuclear separation. This suggests why the use of a simple electrostatics-based model potential to describe the interactions is inadequate.

Assignment of four different spectra obtained by resonance-enhanced multiphoton ionisation spectroscopy (REMPI) is undertaken; these are for the four disubstituted benzene molecules: ortho-difluorobenzene, ortho-chlorofluorobenzene, meta–difluorobenzene and meta- chlorofluorobenzene . Comparing with several previous experimental studies, some results could be compared,and confirms the correctness of the analysis. More generally, the information impacts on how mixed the vibrational motions have become – this directly impacts on how well energy can be dispersed in each molecule.

Item Type: Thesis (University of Nottingham only) (MSc(Res))
Supervisors: Wright, Timothy
Besley, Nicholas
Keywords: Metal Rare Gas Complexes, REMPI spectroscopy
Subjects: Q Science > QD Chemistry > QD450 Physical and theoretical chemistry
Faculties/Schools: UK Campuses > Faculty of Science > School of Chemistry
Item ID: 55563
Depositing User: Zheng, Yu
Date Deposited: 08 Apr 2019 11:14
Last Modified: 07 May 2020 13:47
URI: http://eprints.nottingham.ac.uk/id/eprint/55563

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