Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2016-02-11T13:22:47Z No. of bitstreams: 2 Dissertação - Suélio Marques da Silva Filho - 2015.pdf: 1382344 bytes, checksum: 0e23a66caaf188eae94f6e4452dfc39f (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-02-12T11:03:31Z (GMT) No. of bitstreams: 2 Dissertação - Suélio Marques da Silva Filho - 2015.pdf: 1382344 bytes, checksum: 0e23a66caaf188eae94f6e4452dfc39f (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-02-12T11:03:31Z (GMT). No. of bitstreams: 2 Dissertação - Suélio Marques da Silva Filho - 2015.pdf: 1382344 bytes, checksum: 0e23a66caaf188eae94f6e4452dfc39f (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-10-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this work we present results for static and dynamic hyperpolarizabilities of the lithium salt of pyridazine calcium doped Li􀀀H3C4N2 Ca. The geometry of this molecule was optimized at the MP2 level with the cc-pVQZ basis set of functions through the Gaussian 09 program. We analyzed the level of electronic correlation and optimized a basis set of functions to calculate the hyperpolarizabilities of this molecule. The properties of interest were calculated analytically at the CCSD level with the optimized basis set using the response theory implemented in DALTON 2013 program. The results showed that the doping of the lithium salt of pyridazine is very important for increasing the value of the second hyperpolarizability. When doped with calcium, its value is of the order of 106 atomic units (au), which indicates that this molecule has the potential to be used in nonlinear optical materials. The dependence in relation to the frequency was studied for the following nonlinear optical processes: dc-P and SHG related with the first hyperpolarizability; dc-K, IDRI, dc-SHG and THG related with the second hyperpolarizability. / Neste trabalho apresentamos resultados para hiperpolarizabilidades estáticas e dinâmicas do sal de lítio de piridazina dopado com cálcio Li􀀀H3C4N2 Ca. A geometria desta molécula foi otimizada no nível MP2 com o conjunto de funções base cc-pVQZ, através do programa GAUSSIAN 09. Fizemos uma análise do nível de correlação eletrônica e otimizamos um conjunto de funções base para calcular as hiperpolarizabilidades desta molécula. As propriedades de interesse foram calculadas analiticamente no nível CCSD com o conjunto de funções base otimizado utilizando a teoria de resposta implementada no programa DALTON 2013. Os resultados mostram que a dopagem do sal de lítio de piridazina é muito importante para aumentar o valor da segunda hiperpolarizabilidade. Quando dopado com cálcio, seu valor é da ordem de 106 unidades atômicas (au), o que indica que esta molécula tem potencial para ser utilizada em materiais ópticos não lineares. Foram estudadas as dependências com a frequência dos seguintes processos ópticos não lineares: dc-P e SHG relacionados com a primeira hiperpolarizabilidade; dc-K, IDRI, dc-SHG e THG relacionados com a segunda hiperpolarizabilidade.

Σκοπός της παρούσας διδακτορικής διατριβής ήταν ο προσδιορισμός της υπερπολωσιμότητας δεύτερης τάξης διάφορων φουλλερενίων, παραγώγων φουλλερενίων και διθειολενικών συμπλόκων και η συσχέτιση αυτής με τη χημική δομή των υπό μελέτη υλικών. Για τη μελέτη των μη-γραμμικών οπτικών ιδιοτήτων των υλικών αυτών χρησιμοποιήθηκε η τεχνική Z-scan. Η μη-γραμμική τους απόκριση μελετήθηκε για παλμική διέγερση 35 ps και 8 ns, στα 532 και 1064 nm. Παράγοντες όπως ενίσχυση λόγω συντονισμού, μείωση της συμμετρίας, απεντοπισμός ηλεκτρονίων και μεταφορά φορτίου βρέθηκαν ότι επηρεάζουν σημαντικά τις μη-γραμμικές οπτικές ιδιότητες των συστημάτων αυτών. / The objective of this thesis was the determination of the second-order hyperpolarizability of some fullerenes, fullerene derivatives and dithiolene complexes and the understanding of the relation between the hyperpolarizability and the molecular structure. The non-linear optical properties of the above systems were investigated by the Z-scan technique. In particular, their non-linear optical response was studied under pulsed laser excitation having duration 35 ps and 8 ns, at 532 and 1064 nm. Several factors, like resonant enhancement, symmetry reduction, electron delocalization and charge transfer, were found to influence significantly the non-linear optical properties of these molecules.