Toolkits for simulation and interpretation of photoinduced processes: a mixed classical-quantum approach

doctoral thesis

• Title (croatian): Alati za simulaciju i interpretaciju fotoinduciranih procesa – miješani klasično-kvantni pristup
• Author: Marin Sapunar
• Mentor: Nađa Došlić (mentor)
• Committee member: Tomica Hrenar (predsjednik povjerenstva)
• Committee member: Marko-Tomislav Cvitaš (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: 2021-07-12, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry
• Universal decimal classification (UDC): 54 - Chemistry. Crystallography. Mineralogy

Abstract

Photochemical reactions involve multiple interacting electronic states which means they need to be treated using methods beyond the Born-Oppenheimer approximation. In the current work, contributions are made to mixed classical-quantum methods for studying these reactions. First, highly efficient numerical algorithms were developed to calculate overlap integrals between electronic wave functions at different nuclear configurations. These integrals are essential for nonadiabatic dynamics simulations at the mixed classical-quantum level but are also shown here to be very useful for facilitating the analysis of the electronic states in large ensembles of nuclear configurations. This type of analysis is then used to revisit two prototypical reactions in photochemistry, hydrogen dissociation in pyrrole and internal conversion in pyrazine. In pyrrole, the effect of Rydberg-valence mixing in the bright 𝜋𝜋𝜋𝜋∗ state on the time scale of the reaction is discussed. In pyrazine, the very early population of two n𝜋𝜋∗ states is conclusively proven.

Abstract (croatian)

Fotokemijske reakcije uključuju više elektronskih stanja koja međusobno interagiraju zbog čega se moraju proučavati metodama koje idu dalje od Born-Oppenheimerove aproksimacije. Cilj ovog rada je doprinijeti miješanim klasično-kvantnim metodama za proučavanje takvih reakcija. Razvijeni su vrlo efikasni numerički algoritmi za računanje integrala preklapanja između elektronskih valnih funkcija na različitim geometrijama molekula. Ti integrali nužni su za simulacije neadijabatske dinamike na miješanom klasično-kvantnom nivou, ali ovdje pokazujemo da su i iznimno korisni za analizu elektronskih stanja u velikim ansamblima nuklearnih konfiguracija. Takva analiza je zatim iskorištena za ponovno sagledavanje dvije široko proučavane reakcije u fotokemiji, disocijaciju vodika u pirolu i internu konverziju u pirazinu. Kod pirola se proučava utjecaj miješanja svijetlog valentnog 𝜋𝜋𝜋𝜋∗ stanja s Rydbergovim stanjima na vremensku skalu reakcije, dok se kod pirazina daje dokaz vrlo ranog populiranja dva n𝜋𝜋∗ stanja.

• Keywords: excited states; nonadiabatic dynamics; nuclear ensemble approach; pyrazine; pyrrole; wave function overlaps
• Keywords (english): metoda nuklearnog ansambla; neadijabatska dinamika; pirazin; pirol; pobuđena stanja; preklapanja valnih funkcija
• Language: english
• URN:NBN: urn:nbn:hr:217:767444
• Promotion: 2021
• 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: 130 str. ; 30 cm
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-09-07 12:14:20