Radicals are interesting to study because of importance in so many processes such as semiconductor growth or stellar evolution. Laser induced fluorescence (LIF) and wavelength resolved emission spectra of jet cooled HPS, HAsO, AsD2, H2PS, and F2BO have been measured using the pulsed discharge jet technique. Several bands in the à 1A′′ − X̃ 1A′ transition of HPS were observed and assigned with the help of ab initio calculations. The ab initio geometries showed that HPS does not follow Walsh’s predictions for the angle change upon electronic excitation; Walsh predicts an increase in HPS upon excitation while a decrease is calculated. Ab initio Walsh-style orbital angular correlation diagrams for both electronic states show a change in correlation for some orbitals upon electronic excitation, an effect that Walsh did not predict. The à 1A′′ − X̃ 1A′ transitions were measured in HAsO and DAsO for the first time. A molecular geometry was derived for each electronic state from experimental rotational constants. The experimental geometries prove that HAsO also violates Walsh’s rules for the same reason shown in HPS. The à 2A1 – X̃ 2B1 electronic transition of AsD2 and AsHD were measured. Vibrational levels observed in emission were fit to a local mode vibrational Hamiltonian. Using the previously reported rotational constants for AsH2 and those determined for AsD2 in this work, an improved estimate of the excited state geometry was obtained. The discovery of the B̃ 2A′ − X̃ 2A′ band system of H2PS is the first report of this molecule. Both D2PS and HDPS were also observed. Ab initio calculations helped assign the transition. H2PS is one of the few tetra-atomic or larger molecules that violates Kasha’s empirical rule due to the large separation between the B̃ and à states. Finally, laser induced fluorescence spectra of the F2BO radical was observed for the first time. Previous work showed two band systems with only a tentative assignment. The measured LIF spectra confirm the identity of the two band systems as the B̃ 2A1 – X̃ 2B2 and the B̃ 2A1 – à 2B1 transitions showing F2BO also violates Kasha’s rule.

The continuing need for greater energy security and energy independence has motivated researchers to develop new energy technologies for better energy resource management and efficient energy usage. The focus of this dissertation is the development of optical (spectroscopic) sensing methodologies for various fuels, and energy applications. A fiber-optic NIR sensing methodology was developed for predicting water content in bio-oil. The feasibility of using the designed near infrared (NIR) system for estimating water content in bio-oil was tested by applying multivariate analysis to NIR spectral data. The calibration results demonstrated that the spectral information can successfully predict the bio-oil water content (from 16% to 36%). The effect of ultraviolet (UV) light on the chemical stability of bio-oil was studied by employing laser-induced fluorescence (LIF) spectroscopy. To simulate the UV light exposure, a laser in the UV region (325 nm) was employed for bio-oil excitation. The LIF, as a signature of chemical change, was recorded from bio-oil. From this study, it was concluded that phenols present in the bio-oil show chemical instability, when exposed to UV light. A laser-induced breakdown spectroscopy (LIBS)-based optical sensor was designed, developed, and tested for detection of four important trace impurities in rocket fuel (hydrogen). The sensor can simultaneously measure the concentrations of nitrogen, argon, oxygen, and helium in hydrogen from storage tanks and supply lines. The sensor had estimated lower detection limits of 80 ppm for nitrogen, 97 ppm for argon, 10 ppm for oxygen, and 25 ppm for helium. A chemiluminescence-based spectroscopic diagnostics were performed to measure equivalence ratios in methane-air premixed flames. A partial least-squares regression (PLS-R)-based multivariate sensing methodology was investigated. It was found that the equivalence ratios predicted with the PLS-R-based multivariate calibration model matched with the experimentally measured equivalence ratios within 7 %. A comparative study was performed for equivalence ratios measurement in atmospheric premixed methane-air flames with ungated LIBS and chemiluminescence spectroscopy. It was reported that LIBS-based calibration, which carries spectroscopic information from a “point-like-volume,” provides better predictions of equivalence ratios compared to chemiluminescence-based calibration, which is essentially a “line-of-sight” measurement.

We have investigated the use of deep UV laser induced fluorescence for the sensitive detection and spectroscopic lifetime studies of terbium doped dipicolinic acid (DPA-Tb) and used this to study the optical characteristics of DPA which is a chemical surrounding most bacterial spores. Background absorption spectra, fluorescence spectra, and Excitation Emission Matrix (EEM) spectra were made of the DPA-Tb complex, using both fixed 266 nm wavelength and tunable (220 nm -- 280 nm) UV laser excitations. Of importance, the fluorescence lifetimes of the four main fluorescence peaks (488 nm, 543 nm, 581 nm, and 618 nm) of the DPA-Tb complex have been measured for the first time to our knowledge. The lifetimes of all the fluorescing lines have been measured as a function of DPA-Tb concentration, solvent pH, and solvent composition, including that for the weakest fluorescing line of DPA-Tb at 618 nm. In addition, a new spectroscopic lifetime measurement technique, which we call "Transient Fluorescence Spectroscopy" was developed. In this technique, a weak, quasi-CW, amplitude modulated UV laser (8.5 kHz) was used to measure the lifetimes of the fluorescence lines, and yields insight into energy transfer and excitation lifetimes within the system. This technique is especially useful when a high power laser is not either available or not suitable. In the latter case, this would be when a high power pulsed deep-UV laser could produce bleaching or destruction of the biological specimen. In addition, this technique simulated the excitation and fluorescence emission of the DPA-Tb using a 4-level energy model, and solved the dynamic transient rate equations to predict the temporal behavior of the DPA-Tb emitted fluorescence. Excellent agreement between the experiments and the simulation were found. This technique has the potential to provide a more accurate value for the fluorescence lifetime values. In addition, with the use of asymmetric excitation waveforms, the dynamic transient rate equation analysis may allow for detailed studies of selected transfer mechanisms in a wide range of other spectroscopic applications including rare-earth solid-state lasing materials and biological samples.

This thesis broadly describes the construction of two kinds of spectroscopic set-ups to analyze properties of various materials. In the first part, construction of a Raman spectrometer and a high-throughput in-vivo detection for early plant abiotic stress responses is described. Following which, the set-up is modified into a microscope employed to study Murine blood components with samples varying in age. Initial Raman set-up is also improvised using a polarizer in order to gain deeper understanding of the vibrational and rotational bonds in water. The second part of the thesis explains the construction of a laser-induced fluorescence (LIF) sensor module. Performance testing and experiments were carried out with the sensor module to monitor stress in vegetation and fruits and also detect toxins found in corn and carcinogenic compounds in gasoline. The module was further mounted to an unmanned aerial vehicle for field surveys and preliminary testing in flight is described.

Com clima diversificado e terras férteis, o Brasil tem vocação natural para o desenvolvimento agropecuário e todas as suas vertentes. Assim, o agronegócio é hoje a principal locomotiva da economia brasileira, representando cerca de um terço do nosso Produto Interno Bruto (PIB). Nesse contexto, o Brasil é o terceiro maior produtor de frutas do planeta, com destaque para a produção de laranjas. Particularmente, o país lidera a produção mundial de suco de laranja e conta com uma participação de 85% nas exportações deste produto. Porém, um dos principais fatores atuais que restringem os lucros e a expansão da citricultura é o controle fitossanitário. Atualmente, dentre as principais doenças podemos destacar o HLB e o cancro cítrico. Ambas, doenças bacterianas que não têm cura comprometem a produção e desenvolvimento da fruta e levam à morte da árvore. Dessa maneira, o monitoramento destas é fundamental para evitar danos aos frutos e a necessidade da erradicação de plantações inteiras. O presente trabalho avaliou o emprego das técnicas de Espectroscopia de Fluorescência Induzida por Laser (LIFS) e Espectroscopia de Emissão Óptica com Plasma Induzido por Laser (LIBS) como forma de diagnóstico destas doenças, se apresentando como uma alternativa às inspeções visuais e ao PCR utilizados atualmente. Para isso, folhas de citros in natura provenientes de plantas sadias, com HLB ou com cancro foram amostradas e medidas com ambos os sistemas. Através do sistema LIFS foi realizado um estudo de precocidade no diagnóstico do HLB. Este sistema fotônico pôde detectar a doença até 21 meses antes do aparecimento dos primeiros sintomas visuais. Foram utilizados classificadores sazonais, criados a partir de Regressão por Mínimos Quadrados Parciais (PLSR) e conjuntos de calibração previamente avaliados. Quanto ao cancro cítrico e o sistema LIFS, taxas de acerto superiores a 90% foram alcançadas nos melhores casos de validação cruzada dos dados. A diferenciação do cancro e do HLB também foi possível pela mesma técnica ao avaliar um conjunto pequeno de dados, que atingiu uma taxa de acerto de 82%. Através dos espectros obtidos pelo sistema LIBS, avaliou-se as variações nutricionais causadas na planta devido à doença. Por meio de tais variações e métodos de PLSR foi construído um modelo para o diagnóstico de HLB alcançando taxas de acerto da ordem de 75%. Em relação ao cancro cítrico e o sistema LIBS, um estudo preliminar foi realizado, e uma taxa de acerto superior a 90% foi atingida. Por fim, os resultados corroboraram com a ideia inicial de se realizar o diagnóstico do HLB e do cancro cítrico através de técnicas fotônicas. Dentre outras vantagens estas permitem uma análise rápida, in loco, sem a necessidade de preparo de amostra. Além disso, para o HLB, as técnicas fotônicas demonstraram menor sensibilidade à distribuição não homogênea da doença, quando comparada com a técnica de referência (qPCR). / The diverse climate and fertile soils make Brazil a country with a natural vocation for agricultural development. Thus, agribusiness is now the main locomotive of the Brazilian economy, accounting for about one-third of our Gross Domestic Product (GDP). In this context, Brazil is the third largest fruit producer in the world, with emphasis on the orange production. Particularly, the country leads the world production of orange juice, and with a stake of 85% in exports of this product. However, one of the main factors that restrict current profits and the expansion of citrus production is phytosanitary control. Currently, among the major diseases we highlight the HLB (Greening) and Citrus Canker, two bacterial diseases that have no cure and affect production and fruit development. Therefore, monitoring is essential to prevent damage to the fruits and the complete eradication of infected orchards. The present study evaluated the use of Laser-Induced Fluorescence Spectroscopy (LIFS) and Laser-Induced Breakdown Spectroscopy (LIBS) techniques as alternative diagnostic methods to visual inspection and PCR technique, currently used. For that, citrus leaves from healthy, HLB or citrus canker infected plants, were sampled and measured with both systems. Through LIFS system, a study of the HLB early diagnosis was done. This photonic system could detect the disease up to 21 months before the tree show the visual symptoms. Seasonal classifiers were used, which were designed from Partial Least Square Regression (PLSR) methods and calibration database previously acquired. Regarding citrus canker and LIFS system, success rates higher than 90% were achieved in the best cases. The differentiation between citrus canker and HLB was also possible using the same technique reaching a success rate around 82%. Through the spectrum obtained by LIBS system, it was evaluated the nutritional variations caused in the plant due to HLB, and based on these data, the diagnosis was done. The average success rate was 75%, which was achieved by PLSR model. Regarding on citrus canker and LIBS system, a preliminary study was carried out and a success rate greater than 90% was achieved. Finally, the results corroborated with the use of photonic techniques for the HLB and citrus canker diagnosis. Among other advantages, they allow rapid analysis, in loco and without the need of sample preparation. In addition, for the HLB, photonics techniques showed lower sensitivity to the non-homogeneous distribution of the disease when compared with the reference technique (qPCR).

Com clima diversificado e terras férteis, o Brasil tem vocação natural para o desenvolvimento agropecuário e todas as suas vertentes. Assim, o agronegócio é hoje a principal locomotiva da economia brasileira, representando cerca de um terço do nosso Produto Interno Bruto (PIB). Nesse contexto, o Brasil é o terceiro maior produtor de frutas do planeta, com destaque para a produção de laranjas. Particularmente, o país lidera a produção mundial de suco de laranja e conta com uma participação de 85% nas exportações deste produto. Porém, um dos principais fatores atuais que restringem os lucros e a expansão da citricultura é o controle fitossanitário. Atualmente, dentre as principais doenças podemos destacar o HLB e o cancro cítrico. Ambas, doenças bacterianas que não têm cura comprometem a produção e desenvolvimento da fruta e levam à morte da árvore. Dessa maneira, o monitoramento destas é fundamental para evitar danos aos frutos e a necessidade da erradicação de plantações inteiras. O presente trabalho avaliou o emprego das técnicas de Espectroscopia de Fluorescência Induzida por Laser (LIFS) e Espectroscopia de Emissão Óptica com Plasma Induzido por Laser (LIBS) como forma de diagnóstico destas doenças, se apresentando como uma alternativa às inspeções visuais e ao PCR utilizados atualmente. Para isso, folhas de citros in natura provenientes de plantas sadias, com HLB ou com cancro foram amostradas e medidas com ambos os sistemas. Através do sistema LIFS foi realizado um estudo de precocidade no diagnóstico do HLB. Este sistema fotônico pôde detectar a doença até 21 meses antes do aparecimento dos primeiros sintomas visuais. Foram utilizados classificadores sazonais, criados a partir de Regressão por Mínimos Quadrados Parciais (PLSR) e conjuntos de calibração previamente avaliados. Quanto ao cancro cítrico e o sistema LIFS, taxas de acerto superiores a 90% foram alcançadas nos melhores casos de validação cruzada dos dados. A diferenciação do cancro e do HLB também foi possível pela mesma técnica ao avaliar um conjunto pequeno de dados, que atingiu uma taxa de acerto de 82%. Através dos espectros obtidos pelo sistema LIBS, avaliou-se as variações nutricionais causadas na planta devido à doença. Por meio de tais variações e métodos de PLSR foi construído um modelo para o diagnóstico de HLB alcançando taxas de acerto da ordem de 75%. Em relação ao cancro cítrico e o sistema LIBS, um estudo preliminar foi realizado, e uma taxa de acerto superior a 90% foi atingida. Por fim, os resultados corroboraram com a ideia inicial de se realizar o diagnóstico do HLB e do cancro cítrico através de técnicas fotônicas. Dentre outras vantagens estas permitem uma análise rápida, in loco, sem a necessidade de preparo de amostra. Além disso, para o HLB, as técnicas fotônicas demonstraram menor sensibilidade à distribuição não homogênea da doença, quando comparada com a técnica de referência (qPCR). / The diverse climate and fertile soils make Brazil a country with a natural vocation for agricultural development. Thus, agribusiness is now the main locomotive of the Brazilian economy, accounting for about one-third of our Gross Domestic Product (GDP). In this context, Brazil is the third largest fruit producer in the world, with emphasis on the orange production. Particularly, the country leads the world production of orange juice, and with a stake of 85% in exports of this product. However, one of the main factors that restrict current profits and the expansion of citrus production is phytosanitary control. Currently, among the major diseases we highlight the HLB (Greening) and Citrus Canker, two bacterial diseases that have no cure and affect production and fruit development. Therefore, monitoring is essential to prevent damage to the fruits and the complete eradication of infected orchards. The present study evaluated the use of Laser-Induced Fluorescence Spectroscopy (LIFS) and Laser-Induced Breakdown Spectroscopy (LIBS) techniques as alternative diagnostic methods to visual inspection and PCR technique, currently used. For that, citrus leaves from healthy, HLB or citrus canker infected plants, were sampled and measured with both systems. Through LIFS system, a study of the HLB early diagnosis was done. This photonic system could detect the disease up to 21 months before the tree show the visual symptoms. Seasonal classifiers were used, which were designed from Partial Least Square Regression (PLSR) methods and calibration database previously acquired. Regarding citrus canker and LIFS system, success rates higher than 90% were achieved in the best cases. The differentiation between citrus canker and HLB was also possible using the same technique reaching a success rate around 82%. Through the spectrum obtained by LIBS system, it was evaluated the nutritional variations caused in the plant due to HLB, and based on these data, the diagnosis was done. The average success rate was 75%, which was achieved by PLSR model. Regarding on citrus canker and LIBS system, a preliminary study was carried out and a success rate greater than 90% was achieved. Finally, the results corroborated with the use of photonic techniques for the HLB and citrus canker diagnosis. Among other advantages, they allow rapid analysis, in loco and without the need of sample preparation. In addition, for the HLB, photonics techniques showed lower sensitivity to the non-homogeneous distribution of the disease when compared with the reference technique (qPCR).

Em face ao bom desempenho da agricultura brasileira, cresce também a responsabilidade por uma produção sustentável. Particularmente, o sistema produtivo da cana-de-açúcar vem se adaptando a uma produção sem queima, e busca formas alternativas de manejo dos resíduos da produção que sejam sustentáveis tanto economicamente, quanto ambientalmente. Neste trabalho apresentamos resultados dos tratamentos de solo agriculturável com resíduos de i) cinzas de bagaço de cana aplicado em cobertura e ii) torta de filtro na entrelinha da cultura, em diferentes doses. Avaliamos o impacto desses tratamentos no conteúdo de carbono e na matéria orgânica do solo. Para determinar se os tratamentos podem ser considerados sequestradores de carbono e ambientalmente sustentáveis nos detemos na preservação seletiva como mecanismo de retenção da matéria orgânica do solo, a qual leva a acumulação de componentes orgânicos químicos mais recalcitrantes. Utilizamos as técnicas espectroscópicas de fluorescência de luz UV-Visível, espectroscopia de fluorescência matriz excitação-emissão para avaliar a fração de ácido húmico do solo e o aumento da recalcitrância química, a fluorescência induzida por laser (FIL) para observar a matéria orgânica como um todo e a espectroscopia de emissão ótica com plasma induzido por laser (LIBS) utilizada como uma nova ferramenta para avaliar o conteúdo de carbono do solo. No tratamento de solo com adição de cinza de bagaço de cana tivemos potencial de estoque de carbono na dose 40 t/ha. Quanto a torta de filtro, o carbono total do solo aumenta menos significativamente que na cinza, mas não houve potencial de estoque de carbono. Na fração ácido húmico não observamos modificação do grau de humificação do solo com os tratamentos, mesmo a torta sendo um produto rico em matéria orgânica, porém houve um aumento de grupos carbonílicos, que estão associados ao aumento das interações intermoleculares favorecendo por exemplo a complexação do ácido húmico com metais. Nossos resultados de fluorescência induzida por laser apontam que a cinza possivelmente ofereceu melhora nas condições de crescimento da cultura havendo aumento de grupos alifáticos na MOS. Concluímos portanto, que não houve impacto negativo para o estoque de carbono no solo e qualidade da matéria sob tratamento de adição de cinza de bagaço de cana e torta de filtro. / Given the good performance of Brazilian agriculture, grows the responsibility for sustainable production. Particularly, the sugarcane production system has been adapting to a production without burning, and seeks alternative forms of waste management in production that are both economically and environmentally sustainable. We present results of arable soil treatments with i) sugarcane bagasse ash applied in coverage soil and ii) filter cake applied between the lines of culture in different doses. We assess the impact of these treatments on the content and quality of soil organic matter and carbon sequestration capacity. To determine if treatments can be considered environmentally sustainable and carbon sequestration we embrace the selective preservation as a retention mechanism of soil organic matter, which leads to accumulation of chemical organic compounds recalcitrant. We use bidimensional fluorescence UV-Visible spectroscopy and fluorescence excitation-emission matrix to assess the fraction of soil humic acid, the laser-induced fluorescence spectroscopy (LIF) for observing the whole organic matter and laser breakdown induced spectroscopy (LIBS) used as a new tool to assess the soil carbon content. The soil treatment with sugarcane bagasse ash had increased carbon stock in dose 40 t / ha. In humic acid fraction did not observe any change in the degree of humification treatment with AML, but there was an increase of carbonyl groups, which are associated with increased intermolecular interactions and enhancing the complexation of metals with humic acid. Our results suggest a possible improvement in crop growth conditions with an increase of aliphatic groups in MOS. The filter cake is no carbon content recorded, also did not observe any impact on soil organic matter with the incorporation of filter cake although this is a product rich in organic matter. In this context, we conclude that there was no negative impact on the carbon stock and quality of soil organic matter under treatment addition of sugarcane bagasse ash and filter cake.

Em face ao bom desempenho da agricultura brasileira, cresce também a responsabilidade por uma produção sustentável. Particularmente, o sistema produtivo da cana-de-açúcar vem se adaptando a uma produção sem queima, e busca formas alternativas de manejo dos resíduos da produção que sejam sustentáveis tanto economicamente, quanto ambientalmente. Neste trabalho apresentamos resultados dos tratamentos de solo agriculturável com resíduos de i) cinzas de bagaço de cana aplicado em cobertura e ii) torta de filtro na entrelinha da cultura, em diferentes doses. Avaliamos o impacto desses tratamentos no conteúdo de carbono e na matéria orgânica do solo. Para determinar se os tratamentos podem ser considerados sequestradores de carbono e ambientalmente sustentáveis nos detemos na preservação seletiva como mecanismo de retenção da matéria orgânica do solo, a qual leva a acumulação de componentes orgânicos químicos mais recalcitrantes. Utilizamos as técnicas espectroscópicas de fluorescência de luz UV-Visível, espectroscopia de fluorescência matriz excitação-emissão para avaliar a fração de ácido húmico do solo e o aumento da recalcitrância química, a fluorescência induzida por laser (FIL) para observar a matéria orgânica como um todo e a espectroscopia de emissão ótica com plasma induzido por laser (LIBS) utilizada como uma nova ferramenta para avaliar o conteúdo de carbono do solo. No tratamento de solo com adição de cinza de bagaço de cana tivemos potencial de estoque de carbono na dose 40 t/ha. Quanto a torta de filtro, o carbono total do solo aumenta menos significativamente que na cinza, mas não houve potencial de estoque de carbono. Na fração ácido húmico não observamos modificação do grau de humificação do solo com os tratamentos, mesmo a torta sendo um produto rico em matéria orgânica, porém houve um aumento de grupos carbonílicos, que estão associados ao aumento das interações intermoleculares favorecendo por exemplo a complexação do ácido húmico com metais. Nossos resultados de fluorescência induzida por laser apontam que a cinza possivelmente ofereceu melhora nas condições de crescimento da cultura havendo aumento de grupos alifáticos na MOS. Concluímos portanto, que não houve impacto negativo para o estoque de carbono no solo e qualidade da matéria sob tratamento de adição de cinza de bagaço de cana e torta de filtro. / Given the good performance of Brazilian agriculture, grows the responsibility for sustainable production. Particularly, the sugarcane production system has been adapting to a production without burning, and seeks alternative forms of waste management in production that are both economically and environmentally sustainable. We present results of arable soil treatments with i) sugarcane bagasse ash applied in coverage soil and ii) filter cake applied between the lines of culture in different doses. We assess the impact of these treatments on the content and quality of soil organic matter and carbon sequestration capacity. To determine if treatments can be considered environmentally sustainable and carbon sequestration we embrace the selective preservation as a retention mechanism of soil organic matter, which leads to accumulation of chemical organic compounds recalcitrant. We use bidimensional fluorescence UV-Visible spectroscopy and fluorescence excitation-emission matrix to assess the fraction of soil humic acid, the laser-induced fluorescence spectroscopy (LIF) for observing the whole organic matter and laser breakdown induced spectroscopy (LIBS) used as a new tool to assess the soil carbon content. The soil treatment with sugarcane bagasse ash had increased carbon stock in dose 40 t / ha. In humic acid fraction did not observe any change in the degree of humification treatment with AML, but there was an increase of carbonyl groups, which are associated with increased intermolecular interactions and enhancing the complexation of metals with humic acid. Our results suggest a possible improvement in crop growth conditions with an increase of aliphatic groups in MOS. The filter cake is no carbon content recorded, also did not observe any impact on soil organic matter with the incorporation of filter cake although this is a product rich in organic matter. In this context, we conclude that there was no negative impact on the carbon stock and quality of soil organic matter under treatment addition of sugarcane bagasse ash and filter cake.