Rotational and ro-vibrational spectroscopy of small nitrogen-containing species and their astrophysical applications

Melosso, Mattia (2020) Rotational and ro-vibrational spectroscopy of small nitrogen-containing species and their astrophysical applications, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Chimica, 32 Ciclo.
Documenti full-text disponibili:
[img] Documento PDF (English) - Accesso riservato fino a 31 Dicembre 2022 - Richiede un lettore di PDF come Xpdf o Adobe Acrobat Reader
Disponibile con Licenza: Salvo eventuali più ampie autorizzazioni dell'autore, la tesi può essere liberamente consultata e può essere effettuato il salvataggio e la stampa di una copia per fini strettamente personali di studio, di ricerca e di insegnamento, con espresso divieto di qualunque utilizzo direttamente o indirettamente commerciale. Ogni altro diritto sul materiale è riservato.
Download (7MB) | Contatta l'autore


This thesis presents the study of small nitrogen-bearing molecules, from diatomic radicals to complex organic molecules, by means of rotational and ro-vibrational spectroscopy. Besides their theoretical relevance, which spans from anharmonic force field analyses to energetic and structural properties, I have chosen this family of species because of their astrochemical importance. After some basic knowledge of molecular spectroscopy and astrochemistry is introduced, the instrumentation used during the course of my PhD school is described. Then, the most relevant studies I conducted during the last three years are presented. Generally speaking, a number of molecules of astrophysical relevance have been characterized by means of rotational and ro-vibrational spectroscopy. The sample of studied species is constituted by small radicals (imidogen, amidogen, and titanium nitride), cyanopolyynes (cyanoacetylene) and pre-biotic molecules (aminoacetonitrile): these studies are presented in great detail. Among the results, the first astronomical detection of two deuterated radicals (NHD and ND2) is presented in this thesis.Thanks to our studies, it was possible to clearly identify molecular absorptions of these species towards the pre-stellar core IRAS16293-2422, as recorded by the Herschel Space Observatory mission. These observations confirm the strong deuterium enhancement generally observed in this cloud but they reveal that models underestimate the abundances of NHD and ND2. I also report the detection of vibrationally excited aminoacetonitrile (NH2CH2CN) in Sagittarius B2, as observed in the ReMoCa survey. This is the second detection of aminoacetonitrile in the interstellar medium and the first astronomical observation of its vibrationally hot lines. This represents a small step toward the comprehension on how complex organic molecules are formed and which processes can lead to the formation of glycine. Finally, few general remarks are discussed and the importance of future laboratory studies is pointed out, along with possible perspectives.

Tipologia del documento
Tesi di dottorato
Melosso, Mattia
Dottorato di ricerca
Settore disciplinare
Settore concorsuale
Parole chiave
Rotational spectroscopy; Vibrational spectroscopy; Interstellar species; Radicals; Prebiotic molecules; Astronomical observations
Data di discussione
25 Marzo 2020

Altri metadati

Gestione del documento: Visualizza la tesi