Vpliv ultrahitre molekulske disociacije na Augerjev razpad vrzeli 2p na kloru

Hrast, Mateja (author), Mihelič, Andrej (mentor)

This thesis presents an ab-initio theoretical L-V$^2$ resonant Auger spectrum of the ultrafast dissociating $2p^{-1}_{3/2}\sigma^*$ resonance in HCl. The potential energy curves are calculated as linear combinations of one-configuration states obtained from a DFT calculation. The decay rates are derived within the one-center approximation and based on expanding the molecular orbitals in the atomic ones. A quantum description of nuclear dynamics is considered. Partial amplitudes are derived in terms of Franck-Condon factors using a quasiclassically derived propagator. The calculated profiles of Auger spectral lines resemble those of atomic Auger decay but with the characteristic tails extending towards lower electron kinetic energies. The calculated line asymmetries reflect dissociation dynamics along the potential energy curve of the intermediate state and its relative position with respect to the potential energy curves of the corresponding final states. The shape of the spectral lines is shown to be affected by the variation of the Auger decay rate with the inter-nuclear distance. A good match to the experimental results shows the applicability of our approach to the calculation of the resonant Auger spectra of the ultrafast dissociating molecular states.

• Language: English
• Keywords: Auger decay, Density functional theory, Franck-Condon factor, Inner core-hole, One-center approximation, Potential energy curve, Resonant Auger spectrum, Ultrafast molecular dissociation
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: FMF - Faculty of Mathematics and Physics
• Year: 2024
• PID: 20.500.12556/RUL-158288
• COBISS.SI-ID: 199408387
• Publication date in RUL: 02.06.2024

Secondary language

• Language: Slovenian
• Title: Effect of ultrafast molecular dissociation on the Auger decay of the 2p vacancy in chlorine

Abstract

V disertaciji predstavimo ab initio teoretično obravnavo resonantnega Augerjevega razpada L-V$^2$ iz stanja $2p_{3/2}^{-1}\sigma^*$ v molekuli HCl, ki ultrahitro disociira. Potencialne krivulje izračunamo za enokonfiguracijska stanja z metodo DFT. V približku enega centra izpeljemo izraz za razpadne širine resonantnih stanj, pri čemer molekulske orbitale razvijemo po atomskih. Dinamiko jeder obravnavamo v kvantni sliki. Parcialne amplitude izrazimo s Franck-Condonovimi faktorji in kvaziklasičnim propagatorjem. Izračunane oblike Augerjevih spektralnih črt so podobne tistim iz Augerjeva razpada v atomu, z dodatkom značilnega repa, ki se razteza proti nižjim energijam Augerjevega elektrona. Asimetrija izračunanih črt odraža dinamiko disociacije vzdolž potencialne krivulje vmesnega stanja ter njeno razliko glede na potencialne krivulje končnih stanj. V delu pokažemo učinek spreminjanja Augerjevih razpadnih širin z medjedrsko razdaljo na obliko spektralnih črt. Naši rezultati se dobro ujemajo z meritvijo, kar odraža primernost predstavljene metode za izračun resonantnih Augerjevih spektrov molekul v stanjih, ki ultrahitro disociirajo.

• Keywords: Augerjev razpad, Franck-Condonov faktor, Potencialna krivulja, Približek enega centra, Resonantni Augerjev spekter, Teorija gostotnih funkcionalov (DFT), Ultrahitra molekulska disociacija, Vrzel v notranji lupini