This work presents the design, development, and testing of a field portable imaging spectropolarimeter that operates over the short-wavelength and middle-wavelength portion of the infrared spectrum. The sensor includes a pair of sapphire Wollaston prisms and several high order retarders to produce the first infrared implementation of an imaging Fourier transform spectropolarimeter, providing for the measurement of the complete spectropolarimetric datacube over the passband. The Wollaston prisms serve as a birefringent interferometer with reduced sensitivity to vibration when compared to an unequal path interferometer, such as a Michelson. Polarimetric data are acquired through the use of channeled spectropolarimetry to modulate the spectrum with the Stokes parameter information. The collected interferogram is Fourier filtered and reconstructed to recover the spatially and spectrally varying Stokes vector data across the image.The intent of this dissertation is to provide the reader with a detailed understanding of the steps involved in the development of this infrared hyperspectral imaging polarimeter (IHIP) instrument. First, Chapter 1 provides an overview of the fundamental concepts relevant to this research. These include imaging spectrometers, polarimeters, and spectropolarimeters. A detailed discussion of channeled spectropolarimetry, including a historical study of previous implementations, is also presented. Next a few of the design alternatives that are possible for this work are outlined and discussed in Chapter 2. The configuration that was selected for the IHIP is then presented in detail, including the optical layout, design, and operation. Chapter 3 then presents an artifact reduction technique (ART) that was developed to improve the IHIP's spectropolarimetric reconstructions by reducing errors associated with non-band-limited spectral features. ART is experimentally verified in the infrared using a commercial Fourier transform spectrometer in combination with Yttrium Vanadate as well as Cadmium Sulfide retarders.The remainder of this dissertation then details the testing and analysis of the IHIP instrument. Implementation of ART with the IHIP as well as the employed calibration techniques are described in Chapter 4. Complete calibration of the IHIP includes three distinct processes to provide radiometric, spectral, and polarimetric calibration. With the instrument assembled and calibrated, results and error analyses are presented in Chapter 5. Spectropolarimetric results are obtained in the laboratory as well as outdoors to test the IHIP's real world functionality. The performance of the instrument is also assessed, including experimental measurement of signal-to-noise ratio (SNR), and an analysis of the potential sources of systematic error (such as retarder misalignment and finite polarizer extinction ratio). Chapter 6 presents the design and experimental results for a variable Wollaston prism that can be added to the IHIP to vary the fringe contrast across the field of view. Finally, Chapter 7 includes brief closing remarks summarizing this work and a few observations which may be useful for future infrared imaging Fourier transform channeled spectropolarimeter instruments.

No presente trabalho procurou-se desenvolver um sistema computacional para a automação de um Espectrofotômetro de Varredura Refrativa. Este sistema é baseado em um computador hospedeiro da linha IBM-PC, que pode ser de qualquer modelo, desde que possua barramento ISA de 16 bits. O sistema se divide em dois módulos - aquisição e processamento. O modulo de aquisição e capaz de atingir taxas de aquisição de ate 200 KHz, com resolução de 12 bits. É independente de controle do hospedeiro pois possui lógica de controle e sistema de armazenamento próprio. O módulo de processamento envolve o uso de um processador vetorial de sinais digitais ZORAN ZR34161 dedicado a efetuar eficientemente a Transformada Rápida de Fourier (FFT). Também opera independentemente do computador hospedeiro. Este módulo é capaz de efetuar a FFT em um vetor real de 4096 pontos em 19,64 ms / This work was intended to develop a computational system to control a fast Fourier spectrophotometer. This system is based in an IBM-PC type host computer, with ISA bus 16 bits wide. The system has two modules - acquisition and processing. The acquisition module works at 200 KHz sample rate, with 12 bits of resolution, and also works without host control, due to its own memory system and control logic. The processing module uses a ZORAN ZR34161 vector signal processor, dedicated to do the Fast Fourier Transform (FFT) in the most efficient way. No management of host is required, and it can compute a FFT of a 4096 points real vector in 19,64 ms

Remote sensing of atmospheric gases improves our understanding of the state and evolution of the Earth’s environment. At the beginning of the thesis, the basic principles for the retrieval of concentrations of atmospheric gases from spectra are presented with a focus on ground-based observations. An overview of the characteristic features of different platforms, viewing geometries, measurement sites, and Fourier Transform Spectrometers (FTSs) used in the measurements are provided. The thesis covers four main projects. The first study of the global distribution of atmospheric phosgene was carried out using a total of 5614 measured profiles from the satellite-borne Atmospheric Chemistry Experiment FTS (ACE-FTS) spanning the period February 2004 through May 2006. The phosgene concentrations display a zonally symmetric pattern with the maximum concentration located approximately over the equator, at about 25 km in altitude, and the concentrations decrease towards the poles. A layer of enhanced concentration of phosgene spans the lower stratosphere at all latitudes, with volume mixing ratios of 20-60 pptv. The reasons for the formation of the phosgene distribution pattern are explained by the insolation, lifetime of phosgene and the Brewer-Dobson circulation. The ACE observations show lower phosgene concentrations in the stratosphere than were obtained from previous observations in the 1980s and 1990s due to a significant decrease in source species. The Portable Atmospheric Research Interferometric Spectrometer for the Infrared (PARIS-IR) is a copy of the ACE-FTS that was designed for ground-based and balloon-borne measurements. The first balloon flight was part of the Middle Atmosphere Nitrogen TRend Assessment (MANTRA) 2004 balloon payload. Some useful engineering information was obtained on the thermal performance of the instrument during the flight. As part of the MANTRA program, a ground-based inter-instrument comparison campaign was conducted with the objective of assessing instrument performance, and evaluating data processing routines and retrieval codes. PARIS-IR provides similar quality results for stratospheric species as does the University of Toronto FTS. An advanced study was carried out for the Carbon Cycle science by Fourier Transform Spectroscopy (CC-FTS) mission, which is a proposed future satellite mission to obtain a better understanding of the sources and sinks of greenhouse gases in the Earth’s atmosphere by monitoring total and partial columns of CO2, CH4, N2O, and CO in the near infrared together with the molecular O2 column. To evaluate the spectral regions, resolution, optical components, and spectroscopic parameters required for the mission, ground-based Fourier transform spectra, recorded at Kiruna, Kitt Peak, and Waterloo, were used. Dry air volume mixing ratios of CO2 and CH4 were retrieved from the ground-based observations. A FTS with a spectral resolution of 0.1 cm-1, operating between 2000 and 15000 cm-1, is suggested as the primary instrument for the mission. Further progress in improving the atmospheric retrievals for CO2, CH4 and O2 requires new laboratory measurements to improve the spectroscopic line parameters. Atmospheric observations were made with three FTSs at the Polar Environment Atmospheric Research Laboratory (PEARL) during spring 2006. The vertical column densities of O3, HCl, HNO3, HF, NO2, ClONO2 and NO from PARIS-IR, the Eureka DA8 FTS, and the ACE-FTS show good agreement. Chorine activation and denitrification in the Arctic atmosphere were observed in the extremely cold stratosphere near Eureka, Nunavut, Canada. The observed ozone depletion during the 2006 campaign was attributed to chemical removal.

Remote sensing of atmospheric gases improves our understanding of the state and evolution of the Earth’s environment. At the beginning of the thesis, the basic principles for the retrieval of concentrations of atmospheric gases from spectra are presented with a focus on ground-based observations. An overview of the characteristic features of different platforms, viewing geometries, measurement sites, and Fourier Transform Spectrometers (FTSs) used in the measurements are provided. The thesis covers four main projects. The first study of the global distribution of atmospheric phosgene was carried out using a total of 5614 measured profiles from the satellite-borne Atmospheric Chemistry Experiment FTS (ACE-FTS) spanning the period February 2004 through May 2006. The phosgene concentrations display a zonally symmetric pattern with the maximum concentration located approximately over the equator, at about 25 km in altitude, and the concentrations decrease towards the poles. A layer of enhanced concentration of phosgene spans the lower stratosphere at all latitudes, with volume mixing ratios of 20-60 pptv. The reasons for the formation of the phosgene distribution pattern are explained by the insolation, lifetime of phosgene and the Brewer-Dobson circulation. The ACE observations show lower phosgene concentrations in the stratosphere than were obtained from previous observations in the 1980s and 1990s due to a significant decrease in source species. The Portable Atmospheric Research Interferometric Spectrometer for the Infrared (PARIS-IR) is a copy of the ACE-FTS that was designed for ground-based and balloon-borne measurements. The first balloon flight was part of the Middle Atmosphere Nitrogen TRend Assessment (MANTRA) 2004 balloon payload. Some useful engineering information was obtained on the thermal performance of the instrument during the flight. As part of the MANTRA program, a ground-based inter-instrument comparison campaign was conducted with the objective of assessing instrument performance, and evaluating data processing routines and retrieval codes. PARIS-IR provides similar quality results for stratospheric species as does the University of Toronto FTS. An advanced study was carried out for the Carbon Cycle science by Fourier Transform Spectroscopy (CC-FTS) mission, which is a proposed future satellite mission to obtain a better understanding of the sources and sinks of greenhouse gases in the Earth’s atmosphere by monitoring total and partial columns of CO2, CH4, N2O, and CO in the near infrared together with the molecular O2 column. To evaluate the spectral regions, resolution, optical components, and spectroscopic parameters required for the mission, ground-based Fourier transform spectra, recorded at Kiruna, Kitt Peak, and Waterloo, were used. Dry air volume mixing ratios of CO2 and CH4 were retrieved from the ground-based observations. A FTS with a spectral resolution of 0.1 cm-1, operating between 2000 and 15000 cm-1, is suggested as the primary instrument for the mission. Further progress in improving the atmospheric retrievals for CO2, CH4 and O2 requires new laboratory measurements to improve the spectroscopic line parameters. Atmospheric observations were made with three FTSs at the Polar Environment Atmospheric Research Laboratory (PEARL) during spring 2006. The vertical column densities of O3, HCl, HNO3, HF, NO2, ClONO2 and NO from PARIS-IR, the Eureka DA8 FTS, and the ACE-FTS show good agreement. Chorine activation and denitrification in the Arctic atmosphere were observed in the extremely cold stratosphere near Eureka, Nunavut, Canada. The observed ozone depletion during the 2006 campaign was attributed to chemical removal.

As part of the ExoMars space programme, the 2016 Trace Gas Orbiter mission was announced. The Martian Atmospheric Trace Molecule Occultation Spectrometer (MATMOS) was a proposed Fourier transform spectrometer and solar imager concept pair that would provide for trace gas detection and aerosol observation of the Martian atmosphere. Martian aerosols – namely CO2 crystals, water-ice crystals, and dust – have been observed during past missions; however, observations have failed to fully characterize their physical and optical properties. This thesis presents an analysis of the ability of the proposed imager to determine the pointing of the spacecraft independent of the spectrometer. Furthermore, proof of concept is presenting showing the ability to, in laboratory conditions, characterize the precision and stability of the imager. Finally, window regions in the transmittance spectrum of the Martian atmosphere are determined simulating the Martian atmosphere and viewing geometry.

No presente trabalho procurou-se desenvolver um sistema computacional para a automação de um Espectrofotômetro de Varredura Refrativa. Este sistema é baseado em um computador hospedeiro da linha IBM-PC, que pode ser de qualquer modelo, desde que possua barramento ISA de 16 bits. O sistema se divide em dois módulos - aquisição e processamento. O modulo de aquisição e capaz de atingir taxas de aquisição de ate 200 KHz, com resolução de 12 bits. É independente de controle do hospedeiro pois possui lógica de controle e sistema de armazenamento próprio. O módulo de processamento envolve o uso de um processador vetorial de sinais digitais ZORAN ZR34161 dedicado a efetuar eficientemente a Transformada Rápida de Fourier (FFT). Também opera independentemente do computador hospedeiro. Este módulo é capaz de efetuar a FFT em um vetor real de 4096 pontos em 19,64 ms / This work was intended to develop a computational system to control a fast Fourier spectrophotometer. This system is based in an IBM-PC type host computer, with ISA bus 16 bits wide. The system has two modules - acquisition and processing. The acquisition module works at 200 KHz sample rate, with 12 bits of resolution, and also works without host control, due to its own memory system and control logic. The processing module uses a ZORAN ZR34161 vector signal processor, dedicated to do the Fast Fourier Transform (FFT) in the most efficient way. No management of host is required, and it can compute a FFT of a 4096 points real vector in 19,64 ms

Les travaux présentés dans ce manuscrit sont consacrés à l’étude de la spectroscopie FTIR à très haute résolution de la molécule de fluorure de sulfuryle SO2F2 qui est apparu récemment comme un polluant atmosphérique important. Une très bonne modélisation de son spectre d’absorption est donc essentielle pour les mesures de concentration atmosphérique.Ce manuscrit comporte cinq parties. La première partie de ce travail de thèse concerne les propriétés de la molécule du fluorure de sulfuryle. La deuxième partie décrit le modèle théorique (formalisme tensoriel, Hamiltonien et moment dipolaire effectifs) que nous avons utilisé pour effectuer les analyses. La troisième partie expose les conditions expérimentales des différents spectres que nous avons enregistré à la ligne AILES du synchrotron SOLEIL à Saint-Aubin (Paris). La quatrième partie décrit le logiciel C2vTDS et enfin dans la cinquième partie, nous présentons les résultats des différentes analyses.Cette thèse a été effectuée au sein du Groupe de Spectrométrie Moléculaire et Atmosphérique (GSMA) de l’Université de Reims Champagne-Ardenne et au Laboratoire Dynamique Moléculaire et Matériaux Photoniques (LDMMP) à l’Ecole Nationale Supérieure d’Ingénieurs de l’Université de Tunis. / The work presented in this manuscript is devoted to the study of very high resolution FTIR spectroscopy of the molecule of sulfuryl fluoride, SO2F2, which recently appeared as an important atmospheric pollutant. However, a very good modeling of its absorption spectrum is essential for atmospheric concentration measurements.This manuscript has five parts. The first part deals with the properties of the molecule of sulfuryl fluoride. The second part describes the theoretical model (tensor formalism and effective Hamiltonian and dipole moment) that we used to perform the analyzes. The third part presents the experimental conditions of the different spectra that we recorded at the AILES line of the SOLEIL synchrotron at Saint-Aubin (Paris). The fourth part describes the software C2vTDS and finally in the fifth part we present the results of the different analyzes.This thesis was performed in the Molecular and Atmospheric Spectrometry Group (GSMA) of the University of Reims Champagne-Ardenne and the Laboratory of Molecular Dynamics and Photonic Materials (LDMMP - ENSIT) of the University of Tunis.

L’origine et l’évolution des différentes structures qui peuplent l’au-delà de la photosphère du Soleil, ainsi que les processus qui interviennent dans la dynamique et le chauffage de sa couronne demeurent de nos jours assez peu compris. L’inextricable complexité inhérente aux phénomènes physiques qui gouvernent l’atmosphère externe solaire s’accompagne de l’absence de données adaptées au besoin scientifique. En effet, l’interprétation et la modélisation des « mécanismes » qui raccordent les échanges entre la chromosphère et la couronne dépendent de paramètres d’observation critiques. Il est par exemple essentiel de pouvoir mesurer de larges bandes de températures et densités verticales s’adaptant aux multiples échelles spatiales et temporelles caractéristiques des différents évènements qui se déroulent dans le Soleil. La compréhension de la dynamique des plasmas repose aussi sur l’analyse Doppler de la scène observée. Ceci implique notamment la capacité de combiner des techniques de spectroscopie et d’imagerie simultanément dans le temps. Pour la couronne, le passage à l’UV spatial est incontournable, et relève d’un véritable défi technique. Malgré les excellents progrès technologiques, l’étude UV du Soleil est une science relativement récente, et aucune mission spatiale solaire n’a pu fournir jusqu’à présent une spectro-imagerie combinée et simultanée dans le domaine spectral qui nous intéresse. C’est pour répondre à cette attente que l’étude d’un nouveau dispositif appelé IFTSUV (abréviation de Imaging Fourier Transform Spectrometer working in the far UV), est présentée dans cette recherche. Malgré l’absence de missions d’opportunité dans l’horizon proche, les travaux de thèse se sont déroulés suivant le plan de l’action R&T du CNES R-S11/OT-0004-040, concernant la définition d’un spectro-imageur à transformée de Fourier dans l’UV lointain, et la réalisation en laboratoire d’un démonstrateur de métrologie dédié, pierre angulaire de la faisabilité technique de l’instrument. Ainsi, partant de la détermination du besoin scientifique et de la justification du choix technique, le premier objectif de cette étude est de concevoir un modèle instrumental préliminaire complet de l’IFTSUV. La spécification technique est fondée sur le calcul de dimensionnement et l’évaluation théorique des spécifications en termes de précision spectrale, qualité de l’image et rapport signal sur bruit. A travers l’identification des points durs, la réalisation d’une métrologie d’asservissement du miroir d’échantillonnage apparait tout naturellement, comme un besoin intrinsèque de la validation du concept. En effet, l’acquisition de l’interférogramme doit se faire de manière rigoureusement constante et le pas d’échantillonnage doit être connu avec une grande exactitude, car il fixe les nombres d’onde pour lesquels les spectres bruts sont calculés. Le maquettage d’une solution métrologique constitue donc le deuxième objectif de ce travail. L’architecture optique mise en place a été choisie afin de satisfaire les besoins de stabilité angulaire (< 2.5 μrad) et de précision linéaire (< 8 nm) discernés, et testée en laboratoire. Les résultats sur la maquette valident le concept, même si ses performances s’éloignent des prédictions théoriques. L’évaluation expérimentale des performances permet d’établir des solutions aux problèmes rencontrés qui convergent vers l’optimisation et le prototypage d’un système pouvant être intégré dans une application spatiale. / The origin and evolution of the different structures that inhabit beyond the Sun’s photosphere, as well as the processes involved in the dynamics and the heating of the corona remain quite unknown. The inextricable complexity of the physical phenomena that govern the solar outer atmosphere is accompanied by the lack of suitable data adapted to the scientific need. Indeed, the interpretation and the models of the mechanisms that connect the exchanges between the chromosphere and the corona depend on critical observational parameters. It is for example essential to measure broad bands of vertical temperature and density ranges that fit the multiple spatial and temporal scales that are characteristic of the different events that take place in the Sun. The understanding of the dynamics of the plasma must be also based on the Doppler analysis of the observed scene. That implies the ability to combine time resolved spectroscopic and imaging technologies. Moreover, space is the place to observe the far UV corona and that implies a real technical challenge. Despite excellent advances in technology and instrumentation, the study of the Sun in the far UV is a fairly recent. To date, no solar space mission could provide a combined and simultaneous diagnostic of both observable in the spectral range of interest. It is because of these expectations that the study of a new device called IFTSUV (the acronym of Imaging Fourier Transform Spectrometer working in the far UV) is presented in this research. Despite the lack of opportunity missions on the near horizon, these thesis works have been conducted thanks to the R&D funding R-S11/OT-0004-040 from the CNES, concerning either the definition of an imaging Fourier transform spectrometer in the far UV, or the realization of a laboratory metrology demonstrator that is the cornerstone of the instrument’s feasibility. Thus, starting from the definition of the scientific requirements that lead to the technical choice, the first objective of this study is to develop a preliminary instrumental model of the IFTSUV. The overall technical and design specifications are based in theoreticalcalculations that have been expressed in terms of spectral accuracy, image quality and signal to noise ratio. Throughout the identification of difficult points, the realization of a servo-metrology system dedicated to the sampling mirror appears naturally as an intrinsic need of proof of concept. Indeed, the wavenumbers from the raw spectra are set by the interferogram. That implies that acquisition must be rigorously constant and that the sampling steps must be known with high accuracy. The mockup of a metrological solution is therefore the second objective of this work. The optical breadboard architecture under test has been chosen to meet the needs of angular stability (< 2.5 μrad) and linear accuracy (< 8 nm). The results on the demonstrator validate the concept even if its performances are away from the theoretical predictions. The experimental performance evaluation is used to establish solutions to the instrumental problems encountered. That converge to the optimization and prototyping of a system that could be integrated in a space based application.

Fourier transform infrared emission spectra of MnH and MnD were observed in the ground <em>X</em>⁷&sigma;⁺ electronic state. The vibration-rotation bands from <em>v</em> = 1 to 0 to <em>v</em> = 3 to 2 for MnH, and from <em>v</em> = 1 to 0 to <em>v</em> = 4 to 3 for MnD were recorded at an instrumental resolution of 0. 0085 cm^-1. Spectroscopic constants were determined for each vibrational level and equilibrium constants were found from a Dunham-type fit. The equilibrium vibrational constant <em>&omega;_e</em> for MnH was found to be 1546. 84518(65) cm^-1, the equilibrium rotational constant <em>B_e</em> was found to be 5. 6856789(103) cm^-1 and the equilibrium bond distance <em>r_e</em> was determined to be 1. 7308601(47) Å. <br /><br /> New high resolution emission spectra of CoH and CoD molecules have been recorded in the 640 nm to 3. 5 <em>µ</em>m region using a Fourier transform spectrometer. Many bands were observed for the <em>A</em>^'3&phi;-<em>X</em>³&phi; electronic transition of CoH and CoD. In addition, a new [13. 3]4 electronic state was found by observing the [13. 3]4- <em>X</em>³&phi;₃ and [13. 3]4-<em>X</em>³&phi;₄ transitions in the spectrum of CoD. Analysis of the transitions with &delta;&omega; = 0, ±1 provided more accurate values of spin-orbit splittings between &omega; = 4 and &omega; = 3 components. The ground state for both molecules was fitted both to band and Dunham-type constants. The estimated band constants of the perturbed upper states were also obtained. <br /> <br /> The emission spectrum of gas-phase YbO has been investigated using a Fourier transform spectrometer. A total of 8 red-degraded bands in the range 9 800 ? 11 300 cm^-1 were recorded at a resolution of 0. 04 cm^-1. Because of the multiple isotopomers present in the spectra, only 3 bands were rotationally analyzed. Perturbations were identified in two of these bands and all 3 transitions were found to terminate at the <em>X</em>¹&sigma;⁺ ground electronic state. The electronic configurations that give rise to the observed states are discussed and molecular parameters for all of the analyzed bands are reported. <br /><br /> Electronic spectra of the previously unobserved EuH and EuD molecules were studied by means of Fourier transform spectroscopy and laser-induced fluorescence. The extreme complexity of these transitions made rotational assignments of EuH bands impossible. However, the spin-spin interaction constant, &lambda;, and Fermi contact parameter, <em>b</em>_F, in the ground <em>X</em>⁹&sigma;^- electronic state were estimated for the ¹⁵¹EuH and ¹⁵³EuH isotopologues. <br /><br /> Electronic spectra of SmH, SmCl, TmH and ErF molecules were recorded for the first time using Fourier transform spectrometer. The poor signal to noise ratio of the observed bands coupled with their complexity prevented a rotational analysis. The electronic states that may be involved in the observed transitions are discussed.

Fourier transform infrared emission spectra of MnH and MnD were observed in the ground <em>X</em>⁷&sigma;⁺ electronic state. The vibration-rotation bands from <em>v</em> = 1 to 0 to <em>v</em> = 3 to 2 for MnH, and from <em>v</em> = 1 to 0 to <em>v</em> = 4 to 3 for MnD were recorded at an instrumental resolution of 0. 0085 cm^-1. Spectroscopic constants were determined for each vibrational level and equilibrium constants were found from a Dunham-type fit. The equilibrium vibrational constant <em>&omega;_e</em> for MnH was found to be 1546. 84518(65) cm^-1, the equilibrium rotational constant <em>B_e</em> was found to be 5. 6856789(103) cm^-1 and the equilibrium bond distance <em>r_e</em> was determined to be 1. 7308601(47) Å. <br /><br /> New high resolution emission spectra of CoH and CoD molecules have been recorded in the 640 nm to 3. 5 <em>µ</em>m region using a Fourier transform spectrometer. Many bands were observed for the <em>A</em>^'3&phi;-<em>X</em>³&phi; electronic transition of CoH and CoD. In addition, a new [13. 3]4 electronic state was found by observing the [13. 3]4- <em>X</em>³&phi;₃ and [13. 3]4-<em>X</em>³&phi;₄ transitions in the spectrum of CoD. Analysis of the transitions with &delta;&omega; = 0, ±1 provided more accurate values of spin-orbit splittings between &omega; = 4 and &omega; = 3 components. The ground state for both molecules was fitted both to band and Dunham-type constants. The estimated band constants of the perturbed upper states were also obtained. <br /> <br /> The emission spectrum of gas-phase YbO has been investigated using a Fourier transform spectrometer. A total of 8 red-degraded bands in the range 9 800 ? 11 300 cm^-1 were recorded at a resolution of 0. 04 cm^-1. Because of the multiple isotopomers present in the spectra, only 3 bands were rotationally analyzed. Perturbations were identified in two of these bands and all 3 transitions were found to terminate at the <em>X</em>¹&sigma;⁺ ground electronic state. The electronic configurations that give rise to the observed states are discussed and molecular parameters for all of the analyzed bands are reported. <br /><br /> Electronic spectra of the previously unobserved EuH and EuD molecules were studied by means of Fourier transform spectroscopy and laser-induced fluorescence. The extreme complexity of these transitions made rotational assignments of EuH bands impossible. However, the spin-spin interaction constant, &lambda;, and Fermi contact parameter, <em>b</em>_F, in the ground <em>X</em>⁹&sigma;^- electronic state were estimated for the ¹⁵¹EuH and ¹⁵³EuH isotopologues. <br /><br /> Electronic spectra of SmH, SmCl, TmH and ErF molecules were recorded for the first time using Fourier transform spectrometer. The poor signal to noise ratio of the observed bands coupled with their complexity prevented a rotational analysis. The electronic states that may be involved in the observed transitions are discussed.