Interest in atmospheric chemistry has risen dramatically in the last few years. Topics such as the ozone hole, greenhouse effect with global warming, and climatic change have all become household words. High-resolution FTIR clearly suggests itself as a method of choice for research in this field: The high resolution allows individual rotational-vibrational lines of atmospheric gases to be probed and trace gas concentrations thereby be quantified. Unambiguous quantitative identification of individual species is critical in order to characterize and model the changes in the atmosphere. Also, due to the reduced effect of intermolecular line broadening at lower pressures, the absorption linewidths become narrower at higher altitudes. With sufficient spectral resolution, the composite line profiles can thus be deconvoluted to yield vertical profiles of individual gases.
{"title":"Monitoring of Stratospheric Trace Gases in the Arctic with a New Mobile FTIR Spectrometer","authors":"J. Notholt, A. Keens, S. Wang, T. Johnson","doi":"10.1364/hrfts.1992.fd1","DOIUrl":"https://doi.org/10.1364/hrfts.1992.fd1","url":null,"abstract":"Interest in atmospheric chemistry has risen dramatically in the last few years. Topics such as the ozone hole, greenhouse effect with global warming, and climatic change have all become household words. High-resolution FTIR clearly suggests itself as a method of choice for research in this field: The high resolution allows individual rotational-vibrational lines of atmospheric gases to be probed and trace gas concentrations thereby be quantified. Unambiguous quantitative identification of individual species is critical in order to characterize and model the changes in the atmosphere. Also, due to the reduced effect of intermolecular line broadening at lower pressures, the absorption linewidths become narrower at higher altitudes. With sufficient spectral resolution, the composite line profiles can thus be deconvoluted to yield vertical profiles of individual gases.","PeriodicalId":159025,"journal":{"name":"High Resolution Fourier Transform Spectroscopy","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133761530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For over a decade, users of the FTS at the McMath Solar Telescope of the National Solar Observatory have had access to a simple but precise working wavenumber standard for absorption spectra in the form of a short sealed cell containing 10 or 20 Torr of N2O. Because of the high pressure, the observed wavenumbers are not those of the unperturbed molecule, but a direct calibration of the 0002 band at 4417 cm−1in this cell against the accurately known P(7) transition in CH4 yielded wavenumbers with a precision of the order of 0.000002 cm−1 and an accuracy thought to be at least 0.00001 cm−1 (Brault [1]). Some years later, this band was observed by Pollock, et al. [2] using laser heterodyne techniques, and when our cell values are corrected using the pressure shift which they observed, the absolute agreement is quite satisfactory: (NSO - Pollock, calculated) = 0.000035 ± .0000035 cm−1; note that the absolute uncertainty in Pollock, et al. is quoted as .000080 cm−1.
{"title":"Argon I Standards for Emission Spectrometry","authors":"J. Brault","doi":"10.1364/hrfts.1992.thb2","DOIUrl":"https://doi.org/10.1364/hrfts.1992.thb2","url":null,"abstract":"For over a decade, users of the FTS at the McMath Solar Telescope of the National Solar Observatory have had access to a simple but precise working wavenumber standard for absorption spectra in the form of a short sealed cell containing 10 or 20 Torr of N2O. Because of the high pressure, the observed wavenumbers are not those of the unperturbed molecule, but a direct calibration of the 0002 band at 4417 cm−1in this cell against the accurately known P(7) transition in CH4 yielded wavenumbers with a precision of the order of 0.000002 cm−1 and an accuracy thought to be at least 0.00001 cm−1 (Brault [1]). Some years later, this band was observed by Pollock, et al. [2] using laser heterodyne techniques, and when our cell values are corrected using the pressure shift which they observed, the absolute agreement is quite satisfactory: (NSO - Pollock, calculated) = 0.000035 ± .0000035 cm−1; note that the absolute uncertainty in Pollock, et al. is quoted as .000080 cm−1.","PeriodicalId":159025,"journal":{"name":"High Resolution Fourier Transform Spectroscopy","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114581540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. Butcher, N. Douglas, S. Frandsen, F. Maaswinkel
Astronomical stellar spectrometers have traditionally been based on classical slit/grating designs, which have the considerable advantage of easy incorporation of multi-channel array detectors. With current optical, diffraction grating, and array detector technologies, and for constant optical efficiency, high resolution instruments of this type are found to scale in physical size roughly linearly with telescope aperture. For moderate spectral resolutions and existing telescopes, the ability to record simultaneously a substantial length of spectrum has generally been thought to be an advantage outweighing the inelegant and moderately costly nature of the instruments.
{"title":"A Practical Non-Scanning FTS for Astronomy","authors":"H. Butcher, N. Douglas, S. Frandsen, F. Maaswinkel","doi":"10.1364/hrfts.1989.ma4","DOIUrl":"https://doi.org/10.1364/hrfts.1989.ma4","url":null,"abstract":"Astronomical stellar spectrometers have traditionally been based on classical slit/grating designs, which have the considerable advantage of easy incorporation of multi-channel array detectors. With current optical, diffraction grating, and array detector technologies, and for constant optical efficiency, high resolution instruments of this type are found to scale in physical size roughly linearly with telescope aperture. For moderate spectral resolutions and existing telescopes, the ability to record simultaneously a substantial length of spectrum has generally been thought to be an advantage outweighing the inelegant and moderately costly nature of the instruments.","PeriodicalId":159025,"journal":{"name":"High Resolution Fourier Transform Spectroscopy","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134212803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Bisson, B. Comaskey, J. Conway, C. Haynam, J. Stockdale, E. Worden
The emission spectrum of cerium was recorded on the 1m Fourier transform spectrometer (FTS) at the National Solar Observatory, Kitt Peak, AZ., using a 140Ce electrodeless discharge lamp (EDL) as a source. The frequency range 4,000 to 27,600 cm-1 was covered in two runs while maintaining the EDL parameters as constant as possible. Large UV diodes were used as detectors for the 9,100 to 27,600 cm-1 range and In/Sb detectors were used for the 4,000 to 14,300 cm-1 range. The instrument was intensity calibrated for both ranges using standard lamp scans. A multiplication factor obtained from the overlap region was applied to bring the two regions to the same intensity scale.
{"title":"Branching Ratios of Cerium with the Kitt Peak 1m FTS","authors":"S. Bisson, B. Comaskey, J. Conway, C. Haynam, J. Stockdale, E. Worden","doi":"10.1364/hrfts.1989.tua3","DOIUrl":"https://doi.org/10.1364/hrfts.1989.tua3","url":null,"abstract":"The emission spectrum of cerium was recorded on the 1m Fourier transform spectrometer (FTS) at the National Solar Observatory, Kitt Peak, AZ., using a 140Ce electrodeless discharge lamp (EDL) as a source. The frequency range 4,000 to 27,600 cm-1 was covered in two runs while maintaining the EDL parameters as constant as possible. Large UV diodes were used as detectors for the 9,100 to 27,600 cm-1 range and In/Sb detectors were used for the 4,000 to 14,300 cm-1 range. The instrument was intensity calibrated for both ranges using standard lamp scans. A multiplication factor obtained from the overlap region was applied to bring the two regions to the same intensity scale.","PeriodicalId":159025,"journal":{"name":"High Resolution Fourier Transform Spectroscopy","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116645369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The two molecular spectroscopic databases most widely used in terrestrial atmospheric studies, HITRAN (1) and GEISA (2), have recently released updates which contain extensive revisions of the parameters for many key species. Many of the measurements which contributed to these updates were performed using high-resolution Fourier transform spectrometers. In this paper the updates and revisions to the databases will be summarized, and examples of spectroscopic measurements incorporated in the database updates will be presented. Recent efforts to critically evaluate the spectroscopic databases to meet atmospheric remote sensing requirements will also be reviewed.
{"title":"Contributions of Fourier Transform Spectroscopy to Molecular Databases","authors":"M. A. Smith","doi":"10.1364/hrfts.1992.thc1","DOIUrl":"https://doi.org/10.1364/hrfts.1992.thc1","url":null,"abstract":"The two molecular spectroscopic databases most widely used in terrestrial atmospheric studies, HITRAN (1) and GEISA (2), have recently released updates which contain extensive revisions of the parameters for many key species. Many of the measurements which contributed to these updates were performed using high-resolution Fourier transform spectrometers. In this paper the updates and revisions to the databases will be summarized, and examples of spectroscopic measurements incorporated in the database updates will be presented. Recent efforts to critically evaluate the spectroscopic databases to meet atmospheric remote sensing requirements will also be reviewed.","PeriodicalId":159025,"journal":{"name":"High Resolution Fourier Transform Spectroscopy","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124956682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Felker, G. Hartland, T. Corcoran, L. L. Connell, B. Henson, V. Venturo
There exist a variety of Fourier spectroscopies based on linear interactions with light. These can be powerful tools in high resolution molecular spectroscopy. Recently, Fourier transform version of nonlinear Raman-type spectroscopies have also been developed. These methods will be described and experimental results obtained by them will be presented.
{"title":"Fourier Transform Nonlinear Spectroscopies","authors":"P. Felker, G. Hartland, T. Corcoran, L. L. Connell, B. Henson, V. Venturo","doi":"10.1364/hrfts.1989.ma5","DOIUrl":"https://doi.org/10.1364/hrfts.1989.ma5","url":null,"abstract":"There exist a variety of Fourier spectroscopies based on linear interactions with light. These can be powerful tools in high resolution molecular spectroscopy. Recently, Fourier transform version of nonlinear Raman-type spectroscopies have also been developed. These methods will be described and experimental results obtained by them will be presented.","PeriodicalId":159025,"journal":{"name":"High Resolution Fourier Transform Spectroscopy","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127971603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A program has been initiated in the Atmospheric Chemical Kinetics group in the NOAA Aeronomy laboratory to study the products of gas phase chemical reactions and high resolution spectra of transient species using a high resolution Fourier transform spectrometer (Bomem, Model DA3.002). A quantitative knowledge of gas phase reaction products is essential in order to develop a better understanding of chemical mechanisms important in atmospheric chemistry. The precise spectroscopic information obtained from our high resolution spectroscopic studies of transient species is used to obtain a better characterization of the physical properties of these species and also to provide the data neccessary to measure these species in both laboratory and atmospheric measurements. The Fourier transform experiment we have setup is similar in principle to smog chamber type experiments which have been used very successfully to analyze the stable products of gas phase reactions. The major differences between our apparatus and the smog chamber type are that we employ discharge flow techniques to prepare reactants in lieu of steady state photolysis, we operate at much lower pressures so that absorption lines are not significantly pressure broadened, and we can detect the radical reactants and products themselves, not just the stable products of the reactions.
{"title":"High Resolution Fourier Transform Spectroscopic Studies of the Atmospheric Sciences","authors":"J. Burkholder, J. Orlando, C. J. Howard","doi":"10.1364/hrfts.1989.wb2","DOIUrl":"https://doi.org/10.1364/hrfts.1989.wb2","url":null,"abstract":"A program has been initiated in the Atmospheric Chemical Kinetics group in the NOAA Aeronomy laboratory to study the products of gas phase chemical reactions and high resolution spectra of transient species using a high resolution Fourier transform spectrometer (Bomem, Model DA3.002). A quantitative knowledge of gas phase reaction products is essential in order to develop a better understanding of chemical mechanisms important in atmospheric chemistry. The precise spectroscopic information obtained from our high resolution spectroscopic studies of transient species is used to obtain a better characterization of the physical properties of these species and also to provide the data neccessary to measure these species in both laboratory and atmospheric measurements. The Fourier transform experiment we have setup is similar in principle to smog chamber type experiments which have been used very successfully to analyze the stable products of gas phase reactions. The major differences between our apparatus and the smog chamber type are that we employ discharge flow techniques to prepare reactants in lieu of steady state photolysis, we operate at much lower pressures so that absorption lines are not significantly pressure broadened, and we can detect the radical reactants and products themselves, not just the stable products of the reactions.","PeriodicalId":159025,"journal":{"name":"High Resolution Fourier Transform Spectroscopy","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121661094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A Bomem DA3.002 Fourier transform spectrometer has been modified by replacing the plane moving mirror with a moving roof-top and a stationary retro-reflector. This simple modification results in a maximum optical path difference of about 4.5m and an apparatus function with full width at half maximum of about 0.0014 cm−1. Doppler limited spectra can now be obtained to 600 cm−1 (depending on the species under study) and the maximum resolution has been observed down to 10 cm−1.
{"title":"High Resolution Fourier Transform Spectroscopy from 10 to 1000 cm−1","authors":"J. Johns","doi":"10.1364/hrfts.1989.wa1","DOIUrl":"https://doi.org/10.1364/hrfts.1989.wa1","url":null,"abstract":"A Bomem DA3.002 Fourier transform spectrometer has been modified by replacing the plane moving mirror with a moving roof-top and a stationary retro-reflector. This simple modification results in a maximum optical path difference of about 4.5m and an apparatus function with full width at half maximum of about 0.0014 cm−1. Doppler limited spectra can now be obtained to 600 cm−1 (depending on the species under study) and the maximum resolution has been observed down to 10 cm−1.","PeriodicalId":159025,"journal":{"name":"High Resolution Fourier Transform Spectroscopy","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131453062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We are making a thorough study of the Meinel bands of OH and OD radicals in the spectral region 1900 to 9000 cm−1. Three sources have been used, the ozone-hydrogen flame, the oxygen-acetylene flame, and the inductively coupled plasma (ICP). Differences in the spectra are immediately apparent, as shown in Figure 1. The ozone-hydrogen flame operates at low pressure, the lines are sharp, and the excitation is non-thermal. The oxygen-acetylene flame operates at atmospheric pressure and produces thermal excitation and broad lines. The ICP spectrum is similar to the oxygen-acetylene flame but with lines of intermediate sharpness.
{"title":"Fourier Transform Spectroscopy of OH and OD in the Infrared","authors":"S. Davis, R. Engleman, M. Abrams","doi":"10.1364/hrfts.1989.wa2","DOIUrl":"https://doi.org/10.1364/hrfts.1989.wa2","url":null,"abstract":"We are making a thorough study of the Meinel bands of OH and OD radicals in the spectral region 1900 to 9000 cm−1. Three sources have been used, the ozone-hydrogen flame, the oxygen-acetylene flame, and the inductively coupled plasma (ICP). Differences in the spectra are immediately apparent, as shown in Figure 1. The ozone-hydrogen flame operates at low pressure, the lines are sharp, and the excitation is non-thermal. The oxygen-acetylene flame operates at atmospheric pressure and produces thermal excitation and broad lines. The ICP spectrum is similar to the oxygen-acetylene flame but with lines of intermediate sharpness.","PeriodicalId":159025,"journal":{"name":"High Resolution Fourier Transform Spectroscopy","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125396920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the standard configuration of the high-resolution BOMEM FTIR model 3.002, the infrared source is focused onto an entrance iris whose aperture can be varied from 0.5 to 10 mm diameter. In the mid-infrared the beam from the sample compartment is normally focused onto a 1 mm diameter MCT detector with an elliptical mirror so that an entrance aperture of about 5 mm fills the detector. However, in order to achieve the full resolution of the instrument in the 10 μm region, it is necessary to adjust the iris for about a 1 mm diameter entrance aperture. Under these conditions the detector sees a combination of the hot source and the warm annulus of the iris around the small entrance aperture. Because the hot source is focused onto the iris, the iris is warmer than room temperature. If this warm iris contributes a significant fraction of the radiation seen by the detector, the full resolution expected from the small entrance aperture will not be achieved.
{"title":"Thermal Contamination of BOMEM FTIR Line Shapes","authors":"L. Giver, C. Chackerian, M. Spencer","doi":"10.1364/hrfts.1992.saa5","DOIUrl":"https://doi.org/10.1364/hrfts.1992.saa5","url":null,"abstract":"In the standard configuration of the high-resolution BOMEM FTIR model 3.002, the infrared source is focused onto an entrance iris whose aperture can be varied from 0.5 to 10 mm diameter. In the mid-infrared the beam from the sample compartment is normally focused onto a 1 mm diameter MCT detector with an elliptical mirror so that an entrance aperture of about 5 mm fills the detector. However, in order to achieve the full resolution of the instrument in the 10 μm region, it is necessary to adjust the iris for about a 1 mm diameter entrance aperture. Under these conditions the detector sees a combination of the hot source and the warm annulus of the iris around the small entrance aperture. Because the hot source is focused onto the iris, the iris is warmer than room temperature. If this warm iris contributes a significant fraction of the radiation seen by the detector, the full resolution expected from the small entrance aperture will not be achieved.","PeriodicalId":159025,"journal":{"name":"High Resolution Fourier Transform Spectroscopy","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125188256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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