Miješani kvantno-klasični pristup izračunu i asignaciji vremenski razlučenih fotoelektronskih spektara

doctoral thesis

• Title (english): Mixed quantum-classical approach to the calculation and assignment of the time-resolved photoelectron spectra
• Author: Tomislav Piteša
• Mentor: Nađa Došlić (mentor)
• Committee member: Tomica Hrenar (predsjednik povjerenstva)
• Committee member: Ivan Ljubić (član povjerenstva)
• Committee member: Janez Mavri https://orcid.org/0000-0002-0767-6367 (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2022-02-16, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry
• Universal decimal classification (UDC): 54 - Chemistry. Crystallography. Mineralogy

Abstract

Vremenski razlučena fotoelektronska spektroskopija (TRPES) jedna je od najprikladnijih
pobudno-testnih tehnika za praćenje spregnute nuklearne i elektronske dinamike. Međutim,
kako bi se molekulska dinamika mogla "vidjeti" u spektru, potrebne su teorijske simulacije i
asignacije spektara. U ovom je radu klasični formalizam ulazno-izlaznog probira primjenjen
na TRPES tehinku. Osmišljena je i implementirana pragmatična metodologija izvrednjavanja
izraza, koja se temelji na multireferentnom opisu vezanih elektronskih stanja, miješanoj
kvantno-klasičnoj simulaciji neadijabatske dinamike te opisu fotoionizacijskog kontinuuma
unutar teorije funkcionala gustoće sa statičkom izmjenom. Uz to, osmišljen je i implementiran
jednostavan algoritam za asignaciju TRPES spektra u terminima elektronskih karaktera,
temeljen na dijabatizaciji vezanih elektronskih stanja. Ukupna metodologija je primjenjena
na dva prototipna fotoinducirana procesa, internu konverziju u pirazinu te otvaranje prstena u
cikloheksa-1,3-dienu. Nova saznanja o mehanizmima proučavanih procesa su prezentirana
i raspravljena. Dodatno, simulacijama neadijabatske dinamike proučeni su i mehanizmi
eliminacije dušika iz diazometana prilikom pobude u prvo i drugo pobuđeno stanje.

Abstract (english)

Time-resolved photoelectron spectroscopy (TRPES) has proven to be one of the most convenient pump-probe techniques for monitoring the coupled nuclear and electronic dynamics.
However, in order to "see" the molecular dynamics in the spectrum, the theoretical simulations
and assignment of the spectra are needed. In this work, the classical doorway-window formalism has been applied to the TRPES technique. A pragmatic methodology of evaluation of
the expression has been designed and implemented. It consists of multireference treatment of
bound electronic states, a mixed quantum-classical simulation of nonadiabatic dynamics and
static-exchange DFT treatment of the photoionization continuum. Also, a simple procedure
of TRPES assignment in the terms of electronic characters, based on the diabatization of the
bound electronic states, has been designed and implemented. The methodology as a whole
has been applied on two prototype photoinduced processes: internal conversion in pyrazine
and the ring-opening reaction in cyclohexa-1,3-diene. New insights in the mechanisms of
the studied processes are presented and discussed. In addition, the mechanisms of nitrogen
elimination from diazomethane during excitation to the first and second excited state were
studied by simulations of nonadiabatic dynamics.

• Keywords: fotoelektronska spektroskopija; pobudno-testna spektroskopija; neadijabatksa dinamika; dijabatizacija; fotokemija; pirazin; cikloheksa-1; 3-dien
• Keywords (english): photoelectron spectroscopy; pump-probe spectroscopy; nonadiabatic dynamics; diabatization; photochemistry; pyrazine; 1; 3-cyclohexadiene
• Language: croatian
• URN:NBN: urn:nbn:hr:217:949127
• Promotion: 2022
• Project: Number: IP-2016-06-1142; Title: Svjetlo na molekulama: istraživanje spregnute elektronske i nuklearne dinamike; Acronym: LightMol; Leader: Nađa Došlić; Jurisdiction: Croatia; Funder: HRZZ; Funding stream: IP
• Study programme: Title: Doctoral study in chemistry; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija (doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija)
• Type of resource: Text
• Extent: 127 str. ; 30 cm
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2024-02-16
• Created on: 2022-02-18 13:55:55