Modern Spectroscopy of Solids, Liquids, and Gases最新文献

{"title":"Isotope effects in the pasma-chemical decomposition of carbon dioxide","authors":"S. Andreev, M. A. Kerimkulov, A. Mazurenko, V. Ochkin, S. Savinov, S. Tskhai","doi":"10.1117/12.166222","DOIUrl":"https://doi.org/10.1117/12.166222","url":null,"abstract":"The carbon dioxide dissociation has been investigated both theoretically and experimentally in nonequilibrium plasma of the glow and high-frequency gas discharges. Vibrational and gas temperature values have been measured for molecules in plasma and the dissociation degree for the isotopes 12C16O2 and 13C16O2 after the exit of the gas from the reactor core has been also measured. CARS and absorbtion spectrometry (with help of frequency tuned diode lasers) methods were used for the investigation.","PeriodicalId":266792,"journal":{"name":"Modern Spectroscopy of Solids, Liquids, and Gases","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121091688","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}

{"title":"Fast sub-ppb Trace Gas Detection by Infrared Diode-Laser FM-Spectroscopy","authors":"P. Werle","doi":"10.1364/msslg.1995.ssaa5","DOIUrl":"https://doi.org/10.1364/msslg.1995.ssaa5","url":null,"abstract":"Sensitivity, specifity, high time resolution and cost effective simultaneous measurements of several components using operational systems are the main requirements for atmospheric research and air pollution monitoring1 Tunable diode lasers absorption spectroscopy (TDLAS) is increasingly being used to measure atmospheric trace gas concentrations down to low ppb-levels (10-9 volume mixing ratio). Semiconductor lead salt diode lasers give access to the mid infrared spectral region, where the most important atmospheric constituents have strong rotational vibrational absorption bands. The application of high frequency modulation (FM) schemes can further improve sensitivity and detection speed of modern instrumentation. Operational instruments are needed for fast airborne measurements and sensitive and reliable field measurements. The great number of gaseous pollutants and their generally low variable concentrations with large local differences pose challenging requirements to analytical techniques. Research in atmospheric chemistry requires highly sensitive techniques for measurement of concentrations of free radicals which determine the rate of photochemical destruction of most atmospheric pollutants.","PeriodicalId":266792,"journal":{"name":"Modern Spectroscopy of Solids, Liquids, and Gases","volume":"49 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":"125273390","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}

{"title":"Femtosecond probes of molecular and structural dynamics in liquid water: dependence on temperature and ionic solutes","authors":"W. Lotshaw, P. R. Staver, S. Palese, Lynn Schilling, R. Miller","doi":"10.1364/msslg.1995.sfb3","DOIUrl":"https://doi.org/10.1364/msslg.1995.sfb3","url":null,"abstract":"The transient waveforms measured in the femtosecond time-resolved, optical heterodyne detected Raman-induced Kerr effect in liquid water (fs OHD-RIKE) are interpreted by the combination of a forced oscillator kinetic analysis and modal decomposition of the depolarized Raman spectrum deduced from a fast Fourier transform analysis of the discreetly sampled experimental observable. We recently presented an analysis of the fs OHD-RIKE dynamics observed in room temperature/atmospheric pressure liquid water accounting for the structural/vibrational dynamics over the inverse frequency range 0-600 cm-1[1].","PeriodicalId":266792,"journal":{"name":"Modern Spectroscopy of Solids, Liquids, and Gases","volume":"21 3-4 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":"129737576","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}

{"title":"Diode laser spectroscopy of a fast-axial-flow CO2 laser active medium: vibrational distributions and plasma-chemical reactions","authors":"M. Spiridonov, David Toebaert","doi":"10.1364/msslg.1995.sthb7","DOIUrl":"https://doi.org/10.1364/msslg.1995.sthb7","url":null,"abstract":"The diode laser spectrometer operating in the 4.5 μm region with a spectral resolution of about 10-4cm-1 was applied to investigate the active medium of a DC-excited fast-axial-flow CO2 laser. Detailed distributions of the CO2 molecules over the rotational and vibrational levels in a glow discharge plasma have been obtained, and corresponding temperatures have been derived. The vibrational distribution involves more than 30 levels from all vibrational modes of CO2. The bending and symmetric stretch temperatures were found to be equal, and approximately equal (within experimental error of 2-4%) to the rotational temperature.","PeriodicalId":266792,"journal":{"name":"Modern Spectroscopy of Solids, Liquids, and Gases","volume":"77 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":"115316451","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}

{"title":"Molecular Beam Optical Stark and PPMODR Spectroscopy of Pt Containing Molecules","authors":"T. Steimle, Bo Li, Kookchae Jung","doi":"10.1364/msslg.1995.ssaa4","DOIUrl":"https://doi.org/10.1364/msslg.1995.ssaa4","url":null,"abstract":"Ligated platinum compounds are important in many homogeneous catalytic processes yet there is very little experimental information about the Pt-ligand bond. The most detailed information about bonding comes from the analysis of gas phase spectra recorded at a resolution sufficient to resolve the fine and hyperfine structure and shifts in spectral features caused by the application of static electric and magnetic fields. The advent of the supersonic laser ablation/reaction source (1-4) has eliminated many of the problems associated with the generation molecules containing refractory elements, such as Pt. In our laboratory we use such a molecular beam source in the optical Stark and pump/probe microwave optical double resonance (PPMODR)studies. In both techniques the detected signal is single mode cw-dye laser induced fluorescence (LIF).","PeriodicalId":266792,"journal":{"name":"Modern Spectroscopy of Solids, Liquids, and Gases","volume":"5 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":"122466179","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}

{"title":"Collisional Relaxation in Low-Pressure Photolytic Iodine Lasers","authors":"John William Nicholson, W. Rudolph, J. McIver, G. Hager, R. Tate","doi":"10.1364/msslg.1995.sthb5","DOIUrl":"https://doi.org/10.1364/msslg.1995.sthb5","url":null,"abstract":"When the molecules in a gas are photolyzed by a short exitation pulse, the resulting initial velocity distribution can be broader and have a different mean velocity than the velocity distribution the gas has in thermal equilibrium. The velocity distribution then relaxes into thermal equilibrium, the mechanism for this relaxation being collisional. Using time-resolved Doppler spectroscopy, the corresponding relaxation time for C3F7I at 0.1 Torr has been measured to be approximately 5 μs [1], for example.","PeriodicalId":266792,"journal":{"name":"Modern Spectroscopy of Solids, Liquids, and Gases","volume":"140 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":"123338078","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}

{"title":"High Resolution CCD Spectrography of the Visible Night Airglow","authors":"J. James","doi":"10.1364/msslg.1995.ssab5","DOIUrl":"https://doi.org/10.1364/msslg.1995.ssab5","url":null,"abstract":"Using iterative optical ray-tracing, two plane-grating spectrographs have been designed and constructed which work at F/1.4 with a refrigerated CCD camera having a 1152 × 289 pixel CCD chip, to make spectra of the night airglow. There is a marked gain (about ×50) in sensitivity over current instrumentation.","PeriodicalId":266792,"journal":{"name":"Modern Spectroscopy of Solids, Liquids, and Gases","volume":"268 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":"116246548","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}

{"title":"Laser-Induced Plasma Temperature Determination Using Time-Resolved NH Molecular Spectroscopy","authors":"D. Plemmons, C. Parigger, J. Hornkohl, J. Lewis","doi":"10.1364/msslg.1995.ssab4","DOIUrl":"https://doi.org/10.1364/msslg.1995.ssab4","url":null,"abstract":"Diatomic molecules such as C2, CN, CH, NO and OH are frequently used in combustion diagnostics.1–3 Fluorescence from several of these molecules has been observed in laser-induced breakdown in various gases and previously reported.4,5 Laser induced breakdown in gases is an alternative means by which excited state diatomic molecules can be produced at high temperature - on the order of 5000 K.","PeriodicalId":266792,"journal":{"name":"Modern Spectroscopy of Solids, Liquids, and Gases","volume":"97 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":"125474229","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}

{"title":"Vacuum Ultraviolet Laser / Time-of-flight Spectroscopy of Cl2.","authors":"R. Lipson, S. Dimov, P. Wang, I. Okuda","doi":"10.1364/msslg.1995.sthb2","DOIUrl":"https://doi.org/10.1364/msslg.1995.sthb2","url":null,"abstract":"Vacuum ultraviolet (VUV) spectra of Cl2 are highly irregular due to extensive excited state perturbations, and in the past, have been difficult to interpret1. This situation was offset substantially by the ab initio calculations of Peyerimhoff and Beunker2. They showed that the strongest VUV transition below 145 nm involves a third tier \u0000 \u0000 \u0000 \u0000 \u0000 1\u0000 \u0000 \u0000 \u0000 ∑\u0000 u\u0000 +\u0000 \u0000 \u0000 \u0000 \u0000 \u0000 ion-pair valence state dissociating to Cl+(1Dg) + Cl-(1Sg), which interacts with the near isoenergetic 4pπ \u0000 \u0000 \u0000 \u0000 \u0000 1\u0000 \u0000 \u0000 \u0000 ∑\u0000 u\u0000 +\u0000 \u0000 \u0000 \u0000 \u0000 \u0000 Rydberg state leading to the formation of a double well potential curve, labelled 1 \u0000 \u0000 \u0000 \u0000 \u0000 1\u0000 \u0000 \u0000 \u0000 ∑\u0000 u\u0000 +\u0000 \u0000 \u0000 \u0000 \u0000 \u0000 .","PeriodicalId":266792,"journal":{"name":"Modern Spectroscopy of Solids, Liquids, and Gases","volume":"63 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":"133642561","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}

{"title":"Picosecond-LIF-Spectroscopy with NO in a High Pressure Cell","authors":"A. Knaack, A. Offt, T. Mill, J. Walewski, W. Schade","doi":"10.1364/msslg.1995.sthb6","DOIUrl":"https://doi.org/10.1364/msslg.1995.sthb6","url":null,"abstract":"Flame radicals are fragments of molecules with high reactivity and control the process of combustion to a high degree. Therefore, the knowledge of accurate number densities of these species is very important, e.g. when modelling flames. Because of the relative large cross sections compared to other optical methods, laser-induced fluorescence (LIF) spectroscopy is one of the most sensitive techniques for accurate determination of concentrations and temperatures [1]. However, when LIF is applied for quantitative diagnostics at high pressures (10 bar >p> 1 bar) and high temperatures, which is typical for industrial combustions, several problems associated with the LIF-method itself appear, and limit the accuracy of the method. The laser excites an upper level population of the molecule or atom under investigation, which decays by spontaneous emission and radiationless by collisional induced processes (quenching). The latter one reduces the fluorescence yield considerably, two or three orders of magnitude are typical for atmospheric pressure. If the measurements are performed with a time resolution better than the quenching rates, the LIF-intensities can be used to extract absolute number densities. However, this requires a laser and a detection system with picosecond time resolution. Since important atomic radicals like O, C, N, H or diatomic molecules like NO, CO and OH can only be excited from the ground state via two- or one photon absorption in the spectral range between 200 and 300 nm [2] a powerful ultraviolet laser system is required in these experiments. However, the quantitative interpretation of the picosecond LIF-intensity measurements still needs accurate quenching rate data for the relevant pressures and temperatures and the species that are present in the combustion process. In the data analysis also systematic influences like photodissociation effects by the strong uv-laser pulses have to be considered. Therefore, in this paper improved quenching rate measurements of NO with NO, N2 and O2 for pressures up to p=10 bar, and photodissociation effects of NO are reported.","PeriodicalId":266792,"journal":{"name":"Modern Spectroscopy of Solids, Liquids, and Gases","volume":"24 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":"132501639","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}