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Parigger CG. Cyanide Molecular Laser-Induced Breakdown Spectroscopy with Current Databases. Atoms 2023. [DOI: 10.3390/atoms11040062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023] Open
Abstract
This work discusses diatomic molecular spectroscopy of laser-induced plasma and analysis of data records, specifically signatures of cyanide, CN. Line strength data from various databases are compared for simulation of the CN, B2Σ+⟶X2Σ+, Δv=0 sequence. Of interest are recent predictions using an astrophysical database, i.e., ExoMol, a laser-induced fluorescence database, i.e., LIFBASE, and a program for simulating rotational, vibrational, and electronic spectra, i.e., PGOPHER. Cyanide spectra that are predicted from these databases are compared with line-strength data that have been in use by the author for the last three decades in the analysis of laser–plasma emission spectra. Comparisons with experimental laser–plasma records are communicated as well for spectral resolutions of 33 and 110 picometer. The accuracy of the CN line-strength data is better than one picometer. Laboratory experiments utilize 308 nm, 35 picosecond bursts within an overall 1 nanosecond pulse-width, and 1064 nm, 6 ns pulse-width radiation. Experimental results are compared with predictions. Differences of the databases are elaborated for equilibrium of rotational and vibrational modes and at an internal, molecular temperature of the order of 8,000 Kelvin. Applications of accurate CN data include, for example, combustion diagnosis, chemistry, and supersonic and hypersonic expansion diagnosis. The cyanide molecule is also of interest in the study of astrophysical phenomena.
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Affiliation(s)
- Christian G. Parigger
- Physics and Astronomy Department, University of Tennessee, University of Tennessee Space Institute, Center for Laser Applications, 411 B.H. Goethert Parkway, Tullahoma, TN 37388-9700, USA
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Parigger CG, Helstern CM, Jordan BS, Surmick DM, Splinter R. Laser-Plasma Spectroscopy of Hydroxyl with Applications. Molecules 2020; 25:E988. [PMID: 32098440 PMCID: PMC7070330 DOI: 10.3390/molecules25040988] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 02/18/2020] [Accepted: 02/20/2020] [Indexed: 11/19/2022] Open
Abstract
This article discusses laser-induced laboratory-air plasma measurements and analysis of hydroxyl (OH) ultraviolet spectra. The computations of the OH spectra utilize line strength data that were developed previously and that are now communicated for the first time. The line strengths have been utilized extensively in interpretation of recorded molecular emission spectra and have been well-tested in laser-induced fluorescence applications for the purpose of temperature inferences from recorded data. Moreover, new experiments with Q-switched laser pulses illustrate occurrence of molecular recombination spectra for time delays of the order of several dozen of microseconds after plasma initiation. The OH signals occur due to the natural humidity in laboratory air. Centrifugal stretching of the Franck-Condon factors and r-centroids are included in the process of determining the line strengths that are communicated as a Supplementary File. Laser spectroscopy applications of detailed OH computations include laser-induced plasma and combustion analyses, to name but two applications. This work also includes literature references that address various diagnosis applications.
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Affiliation(s)
- Christian G. Parigger
- Physics and Astronomy Department, University of Tennessee, University of Tennessee Space Institute, Center for Laser Applications, 411 B.H. Goethert Parkway, Tullahoma, TN 37388-9700, USA;
| | - Christopher M. Helstern
- Physics and Astronomy Department, University of Tennessee, University of Tennessee Space Institute, Center for Laser Applications, 411 B.H. Goethert Parkway, Tullahoma, TN 37388-9700, USA;
| | - Benjamin S. Jordan
- Nuclear Engineering Department, Tickle College of Engineering, University of Tennessee, 1412 Circle Drive, Knoxville, TN 37912, USA;
| | - David M. Surmick
- Physics and Applied Physics Department, University of Massachusetts Lowell, Lowell, MA 01854, USA;
| | - Robert Splinter
- Wellinq Medical, Van der Waals Park 22, 9351 VC Leek, The Netherlands;
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Shattan MB, Gragston M, Zhang Z, Auxier JD, McIntosh KG, Parigger CG. Mapping of Uranium in Surrogate Nuclear Debris Using Laser-Induced Breakdown Spectroscopy (LIBS). Appl Spectrosc 2019; 73:591-600. [PMID: 30990068 DOI: 10.1177/0003702819842871] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
This work describes the use of a laser-induced breakdown spectroscopy (LIBS) system to conduct macroscopic elemental mapping of uranium and iron on the exterior surface and interior center cross-section of surrogate nuclear debris for the first time. The results suggest that similar LIBS systems could be packaged for use as an effective instrument for screening samples during collection activities in the field or to conduct process control measurements during the production of debris surrogates. The technique focuses on the mitigation of chemical and physical matrix effects of four uranium atomic emission lines, relatively free of interferences and of good analytical value. At a spatial resolution of 0.5 mm, a material fractionation pattern in the surrogate debris is identified and discussed in terms of constituent melting temperatures and thermal gradients experienced.
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Affiliation(s)
- Michael B Shattan
- 1 Department of Engineering Physics, Air Force Institute of Technology, Wright Patterson AFB, OH, USA
- 2 Department of Nuclear Engineering, The University of Tennessee, Knoxville, TN, USA
| | - Mark Gragston
- 3 Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee, Knoxville, TN, USA
| | - Zhili Zhang
- 3 Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee, Knoxville, TN, USA
| | - John D Auxier
- 2 Department of Nuclear Engineering, The University of Tennessee, Knoxville, TN, USA
- 4 INS-The Institute for Nuclear Security, Knoxville, TN, USA
| | - Kathryn G McIntosh
- 5 Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM, USA
| | - Christian G Parigger
- 6 Department of Physics and Astronomy, The University of Tennessee, University of Tennessee Space Institute, Tullahoma, TN, USA
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Gautam G, Parigger CG, Helstern CM, Drake KA. Emission spectroscopy of expanding laser-induced gaseous hydrogen-nitrogen plasma. Appl Opt 2017; 56:9277-9284. [PMID: 29216100 DOI: 10.1364/ao.56.009277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 10/19/2017] [Indexed: 06/07/2023]
Abstract
Microplasma is generated in an ultra-high-pure H2 and N2 gas mixture with a Nd:YAG laser device that is operated at the fundamental wavelength of 1064 nm. The gas mixture ratio of H2 and N2 is 9 to 1 at a pressure of 1.21 ± 0.03 105 Pa inside a chamber. A Czerny-Turner-type spectrometer and an intensified charge-coupled device are utilized for the recording of plasma emission spectra. The line-of-sight measurements are Abel inverted to determine the radial distributions of electron number density and temperature. Recently derived empirical formulas are utilized for the extraction of values for electron density. The Boltzmann plot and line-to-continuum methods are implemented for the diagnostic of electron excitation temperature. The expansion speed of the plasma kernel maximum electron temperature amounts to 1 km/s at a time delay of 300 ns. The microplasma, initiated by focusing 14 ns, 140 mJ pulses, can be described by an isentropic expansion model.
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Trautner S, Jasik J, Parigger CG, Pedarnig JD, Spendelhofer W, Lackner J, Veis P, Heitz J. Corrigendum to "Laser-induced optical breakdown spectroscopy of polymer materials based on evaluation of molecular emission bands" [Spectrochim. Acta A Mol. Biomol. Spectrosc. 174 (2017) 331-338]. Spectrochim Acta A Mol Biomol Spectrosc 2017; 179:73. [PMID: 28214678 DOI: 10.1016/j.saa.2017.02.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Affiliation(s)
- Stefan Trautner
- Institute of Applied Physics, Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria
| | - Juraj Jasik
- Institute of Applied Physics, Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria; Department of Organic Chemistry, Charles University in Prague, Hlavova 2030/8, 128 43 Prague 2, Czech Republic; Center for Laser Applications, The University of Tennessee Space Institute, Tullahoma, TN 37388-9700, USA
| | - Christian G Parigger
- Center for Laser Applications, The University of Tennessee Space Institute, Tullahoma, TN 37388-9700, USA
| | - Johannes D Pedarnig
- Institute of Applied Physics, Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria
| | | | | | - Pavel Veis
- Department of Experimental Physics, Physics and Informatics, Comenius University, Mlynska Dolina F2, 842 48 Bratislava, Slovakia
| | - Johannes Heitz
- Institute of Applied Physics, Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria.
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Trautner S, Jasik J, Parigger CG, Pedarnig JD, Spendelhofer W, Lackner J, Veis P, Heitz J. Laser-induced optical breakdown spectroscopy of polymer materials based on evaluation of molecular emission bands. Spectrochim Acta A Mol Biomol Spectrosc 2017; 174:331-338. [PMID: 27984754 DOI: 10.1016/j.saa.2016.11.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 11/24/2016] [Accepted: 11/26/2016] [Indexed: 06/06/2023]
Abstract
Laser-induced breakdown spectroscopy (LIBS) for composition analysis of polymer materials results in optical spectra containing atomic and ionic emission lines as well as molecular emission bands. In the present work, the molecular bands are analyzed to obtain spectroscopic information about the plasma state in an effort to quantify the content of different elements in the polymers. Polyethylene (PE) and a rubber material from tire production are investigated employing 157nmF2 laser and 532nm Nd:YAG laser ablation in nitrogen and argon gas background or in air. The optical detection reaches from ultraviolet (UV) over the visible (VIS) to the near infrared (NIR) spectral range. In the UV/VIS range, intense molecular emissions, C2 Swan and CN violet bands, are measured with an Echelle spectrometer equipped with an intensified CCD camera. The measured molecular emission spectra can be fitted by vibrational-rotational transitions by open access programs and data sets with good agreement between measured and fitted spectra. The fits allow determining vibrational-rotational temperatures. A comparison to electronic temperatures Te derived earlier from atomic carbon vacuum-UV (VUV) emission lines show differences, which can be related to different locations of the atomic and molecular species in the expanding plasma plume. In the NIR spectral region, we also observe the CN red bands with a conventional CDD Czerny Turner spectrometer. The emission of the three strong atomic sulfur lines between 920 and 925nm is overlapped by these bands. Fitting of the CN red bands allows a separation of both spectral contributions. This makes a quantitative evaluation of sulfur contents in the start material in the order of 1wt% feasible.
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Affiliation(s)
- Stefan Trautner
- Institute of Applied Physics, Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria
| | - Juraj Jasik
- Institute of Applied Physics, Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria; Department of Organic Chemistry, Charles University in Prague, Hlavova 2030/8, 128 43 Prague 2, Czech Republic; Center for Laser Applications, The University of Tennessee Space Institute, Tullahoma, TN 37388-9700, USA
| | - Christian G Parigger
- Center for Laser Applications, The University of Tennessee Space Institute, Tullahoma, TN 37388-9700, USA
| | - Johannes D Pedarnig
- Institute of Applied Physics, Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria
| | | | | | - Pavel Veis
- Department of Experimental Physics, Physics and Informatics, Comenius University, Mlynska dolina F2, 842 48 Bratislava, Slovakia
| | - Johannes Heitz
- Institute of Applied Physics, Johannes Kepler University, Altenberger Straße 69, 4040 Linz, Austria.
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Abstract
The spectroscopy of alkaline earth metal compounds is stimulated by the use of these compounds in practical areas ranging from technology to medicine. Applications in the field of pyrotechnics were the motivation for a series of flame emission spectroscopy experiments with strontium-containing compounds. Specifically, strontium monoxide (SrO) was studied as a candidate radiator for the diagnosis of methane-air flames. Strontium monoxide emissions have been observed in flames with temperatures in the range 1200 K to 1600 K for two compounds: strontium hydroxide and strontium chloride. Comparisons are made of the measured SrO spectra to simulated spectra in the near-infrared region of 700 nm to 900 nm.
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Affiliation(s)
- Bobby J Wimberly
- Center for Laser Applications, The University of Tennessee Space Institute, USA
| | - James O Hornkohl
- Center for Laser Applications, The University of Tennessee Space Institute, USA
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Abstract
Spectral measurements of the H(α) Balmer series line and the continuum radiation are applied to draw inferences of electron density, temperature, and the level of self-absorption in laser ablation of a solid ice target in ambient air. Electron densities of 17 to 3.2×10(24) m(-3) are determined from absolute calibrated emission coefficients for time delays of 100-650 ns after generation of laser plasma using Q-switched Nd:YAG radiation. The corresponding temperatures of 4.5-0.95 eV were evaluated from the absolute spectral radiance of the continuum at the longer wavelengths. The redshifted, Stark-broadened hydrogen alpha line emerges from the continuum radiation after a time delay of 300 ns. The electron densities inferred from power law formulas agree with the values obtained from the plasma emission coefficients.
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Parigger CG, Swafford LD, Surmick DM, Witte MJ, Woods AC, Gautam G. Hydrogen Alpha Self-Absorption Effects in Laser-Induced Air Plasma. ACTA ACUST UNITED AC 2014. [DOI: 10.1088/1742-6596/548/1/012043] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Parigger CG, Woods AC, Witte MJ, Swafford LD, Surmick DM. Measurement and analysis of atomic hydrogen and diatomic molecular AlO, C2, CN, and TiO spectra following laser-induced optical breakdown. J Vis Exp 2014:e51250. [PMID: 24561875 DOI: 10.3791/51250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
In this work, we present time-resolved measurements of atomic and diatomic spectra following laser-induced optical breakdown. A typical LIBS arrangement is used. Here we operate a Nd:YAG laser at a frequency of 10 Hz at the fundamental wavelength of 1,064 nm. The 14 nsec pulses with anenergy of 190 mJ/pulse are focused to a 50 µm spot size to generate a plasma from optical breakdown or laser ablation in air. The microplasma is imaged onto the entrance slit of a 0.6 m spectrometer, and spectra are recorded using an 1,800 grooves/mm grating an intensified linear diode array and optical multichannel analyzer (OMA) or an ICCD. Of interest are Stark-broadened atomic lines of the hydrogen Balmer series to infer electron density. We also elaborate on temperature measurements from diatomic emission spectra of aluminum monoxide (AlO), carbon (C2), cyanogen (CN), and titanium monoxide (TiO). The experimental procedures include wavelength and sensitivity calibrations. Analysis of the recorded molecular spectra is accomplished by the fitting of data with tabulated line strengths. Furthermore, Monte-Carlo type simulations are performed to estimate the error margins. Time-resolved measurements are essential for the transient plasma commonly encountered in LIBS.
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Affiliation(s)
| | | | - Michael J Witte
- Department of Physics, University of Tennessee Space Institute
| | | | - David M Surmick
- Department of Physics, University of Tennessee Space Institute
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Parigger CG, Woods AC, Surmick DM, Donaldson AB, Height JL. Aluminum flame temperature measurements in solid propellant combustion. Appl Spectrosc 2014; 68:362-366. [PMID: 24666953 DOI: 10.1366/13-07234] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The temperature in an aluminized propellant is determined as a function of height and plume depth from diatomic AlO and thermal emission spectra. Higher in the plume, 305 and 508 mm from the burning surface, measured AlO emission spectra show an average temperature with 1σ errors of 2980 ± 80 K. Lower in the plume, 152 mm from the burning surface, an average AlO emission temperature of 2450 ± 100 K is inferred. The thermal emission analysis yields higher temperatures when using constant emissivity. Particle size effects along the plume are investigated using wavelength-dependent emissivity models.
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Affiliation(s)
- Christian G Parigger
- The University of Tennessee Space Institute, Center for Laser Applications, 411 B.H. Goethert Parkway, Tullahoma, TN 37388 USA
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Swafford LD, Parigger CG. Laser-induced plasma spectroscopy of hydrogen Balmer series in laboratory air. Appl Spectrosc 2014; 68:1016-1020. [PMID: 25226255 DOI: 10.1366/13-07388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Stark-broadened emission profiles for the hydrogen alpha and beta Balmer series lines in plasma are measured to characterize electron density and temperature. Plasma is generated using a typical laser-induced breakdown spectroscopy (LIBS) arrangement that employs a focused Q-switched neodymium-doped yttrium aluminum garnet (Nd : YAG) laser, operating at the fundamental wavelength of 1064 nm. The temporal evolution of the hydrogen Balmer series lines is explored using LIBS. Spectra from the plasma are measured following laser-induced optical breakdown in laboratory air. The electron density is primarily inferred from the Stark-broadened experimental data collected at various time delays. Due to the presence of nitrogen and oxygen in air, the hydrogen alpha and beta lines become clearly discernible from background radiation for time delays of 0.4 and 1.4 μs, respectively.
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Affiliation(s)
- Lauren D Swafford
- University of Tennessee Space Institute, The Center for Laser Applications, 411 B.H. Goethert Parkway, Tullahoma, TN 37388 USA
| | - Christian G Parigger
- University of Tennessee Space Institute, The Center for Laser Applications, 411 B.H. Goethert Parkway, Tullahoma, TN 37388 USA
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Zuhlke CA, Bruce J, Anderson TP, Alexander DR, Parigger CG. A fundamental understanding of the dependence of the laser-induced breakdown spectroscopy (LIBS) signal strength on the complex focusing dynamics of femtosecond laser pulses on either side of the focus. Appl Spectrosc 2014; 68:1021-1029. [PMID: 25226256 DOI: 10.1366/13-07387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We correlate the focusing dynamics of 50 femtosecond (fs) laser radiation as it interacts with a silicon sample to laser-induced breakdown spectroscopy (LIBS) signal strength. Presented are concentric ring-shaped variations in the electric field in the prefocus region due to lens aberrations and nonsymmetry between the prefocus and post-focus beam profile as a result of continuum generation, occurring around the focus. Experimental results show different signal trends for both atmospheric and vacuum conditions, attributed to the existence of a continuum for the former. Lens aberrations effects on the LIBS signal strength are investigated using a plano-convex spherical lens and an aspherized achromatic lens. High-resolution scanning electron micrographs of the silicon surface after ablation, along with theoretical simulations, reveal the electric field patterns near the focus. The research results contribute to fundamental understanding of the basic physics of ultrashort, femtosecond laser radiation interacting with materials.
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Affiliation(s)
- Craig A Zuhlke
- Electrical Engineering Department, 209N WSEC Link, University of Nebraska, Lincoln, NE 68588 USA
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Witte MJ, Parigger CG, Bullock NA, Merten JA, Allen SD. Carbon swan spectra measurements following breakdown of nitro compound explosive simulants. Appl Spectrosc 2014; 68:367-370. [PMID: 24666954 DOI: 10.1366/13-07230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Our measurements of micro-plasma following laser-induced optical breakdown of nitro compound explosive simulants, here 3-nitrobenzoic acid, show well-developed molecular spectra during the first several hundreds of nanoseconds. Analysis of recorded carbon spectra is accomplished using accurate line strengths for the diatomic molecular Swan system. Presence of hydrogen-beta allows us to infer electron density in the plasma evolution. Computational challenges include accounting for background variation and appropriate modeling of hydrogen embedded in molecular spectra. Recorded and computed spectra agree nicely for time delays on the order of 1.6 μs from optical breakdown when using a single temperature for local thermodynamic equilibrium plasma.
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Affiliation(s)
- Michael J Witte
- University of Tennessee Space Institute, Center for Laser Applications, Tullahoma, TN 37388 USA
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Abstract
We report temperature inferences from time-resolved emission spectra of a micro-sized plasma following laser ablation of an aluminum sample. The laser-induced breakdown event is created with the use of nanosecond pulsed laser radiation. Plasma temperatures are inferred from the aluminum monoxide spectroscopic emissions of the aluminum sample by fitting experimental to theoretically calculated spectra with a nonlinear fitting algorithm. The synthetic spectra used as a comparison for the experimental spectra are generated from accurate line strengths of aluminum monoxide bands. The inferred plasma temperatures are found to be 5315 ± 100 K at 20 μs following breakdown. At later time delays of 45 and 70 μs following breakdown, the plasma temperatures are found to be 4875 ± 95 and 4390 ± 80 K, respectively. Error analysis of the inferred temperatures is performed with the fitting algorithm.
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Affiliation(s)
- David M Surmick
- The Center for Laser Applications, The University of Tennessee Space Institute, 411 B.H. Goethert Parkway, Tullahoma, TN 37388 USA
| | - Christian G Parigger
- The Center for Laser Applications, The University of Tennessee Space Institute, 411 B.H. Goethert Parkway, Tullahoma, TN 37388 USA
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Parigger CG, Johnson JA, Splinter R. Optical diagnostic and therapy applications of femtosecond laser radiation using lens-axicon focusing. Annu Int Conf IEEE Eng Med Biol Soc 2013; 2013:374-7. [PMID: 24109702 DOI: 10.1109/embc.2013.6609515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Diagnostic modalities by means of optical and/or near infrared femtosecond radiation through biological media can in principle be adapted to therapeutic applications. Of specific interest are soft tissue diagnostics and subsequent therapy through hard tissue such as bone. Femto-second laser pulses are delivered to hydroxyapatite representing bone, and photo-acoustic spectroscopy is presented in order to identify the location of optical anomalies in an otherwise homogeneous medium. Imaging through bone is being considered for diagnostic, and potentially therapeutic, applications related to brain tumors. The use of mesomeric optics such as lens-axicon combinations is of interest to achieve the favorable distribution of focused radiation. Direct therapy by increasing local temperature to induce hyperthermia is one mode of brain tumor therapy. This can be enhanced by seeding the tumor with nanoparticles. Opto-acoustic imaging using femtosecond laser radiation is a further opportunity for diagnosis.
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Abstract
We present results including measurement and analysis of titanium monoxide. Pulsed, nanosecond Nd:YAG laser radiation is used in a typical laser-induced breakdown spectroscopy arrangement to record the spectra. This scheme provides experiments analogous to pulsed laser deposition tactics and allows for time-resolved spectroscopic analysis. The computed spectra are generated from a new, accurate line-strength file that allows us to accurately predict γ (A3Φ→X3Δ) and γ' (B3Π→X3Δ) spectral signatures. We infer temperature on the order of 3600±700 K and 4200±800 K at time delays of 52 and 72 μs, respectively. Current interest in this work includes titania (TiO2) nanoparticle generation for thin film applications.
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Affiliation(s)
- Alexander C Woods
- Center for Laser Applications, University of Tennessee Space Institute, Tullahoma, Tennessee 37388, USA
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G. Parigger C. Computational Physics Activities at the University of Tennessee Space Institute. Comput Sci Eng 2012. [DOI: 10.1109/mcse.2012.48] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Parigger CG, Woods A, Hornkohl JO. Analysis of time-resolved superposed atomic hydrogen Balmer lines and molecular diatomic carbon spectra. Appl Opt 2012; 51:B1-B6. [PMID: 22410906 DOI: 10.1364/ao.51.0000b1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 11/18/2011] [Indexed: 05/31/2023]
Abstract
We present analysis of superposition spectra following laser-induced breakdown (LIB) of methane. Both hydrogen-beta and hydrogen-gamma lines contain discernible contributions from diatomic carbon emissions for time delays of 1 to 2 μs from pulsed, 8 ns, infrared Nd:YAG laser radiation LIB. Analysis of the atomic lines and molecular C(2) spectra reveal electron and molecular excitation temperatures of typically 13,000 and 5000 K, respectively.
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Affiliation(s)
- Christian G Parigger
- The University of Tennessee Space Institute, 411 B. H. Goethert Parkway, Tullahoma, Tennessee 37388, USA.
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Parigger CG, Woods AC, Keszler A, Nemes L, Hornkohl JO. Titanium monoxide spectroscopy following laser-induced optical breakdown. ACTA ACUST UNITED AC 2012. [DOI: 10.1063/1.4739915] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Parigger CG, Hornkohl JO. Computation of AlO B2Σ+ → X2Σ+ emission spectra. Spectrochim Acta A Mol Biomol Spectrosc 2011; 81:404-411. [PMID: 21798795 DOI: 10.1016/j.saa.2011.06.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 06/11/2011] [Accepted: 06/16/2011] [Indexed: 05/31/2023]
Abstract
Application of molecular spectroscopy to analytical chemistry usually requires accurate description of the particular transition of interest. In this communication we describe the creation of a list of spectral lines. Following the introduction and definition of the line strength, we present a recipe for computation of diatomic-line-strengths, including the Hönl-London factor and electric dipole line strength for each spectral line. The diatomic eigenfunction is discussed including Hund's case basis functions. In our data tables we prefer use of Hund's case (a) basis, and we apply the usual Born-Oppenheimer approximation for the electronic-vibrational strengths. This allows us to generate the table of line strengths that we frequently apply for spectroscopic temperature determination. Using these line-strength tables, we present theoretical AlO emission spectra for the B-X system of AlO. These emission spectra are computed for temperatures of 3000 and 6000 K and for typical spectroscopic resolution used in laser-induced optical breakdown studies.
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Affiliation(s)
- Christian G Parigger
- The University of Tennessee Space Institute, Center for Laser Applications, 411 B.H. Goethert Parkway, Tullahoma, TN 37388, USA.
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Parigger CG, Dackman M, Hornkohl JO. Time-resolved spectroscopy measurements of hydrogen-alpha, -beta, and -gamma emissions. Appl Opt 2008; 47:G1-G6. [PMID: 19122690 DOI: 10.1364/ao.47.0000g1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Hydrogen emission spectroscopy results are reported following laser-induced optical breakdown with infrared Nd:YAG laser radiation focused into a pulsed methane flow. Measurements of Stark-broadened atomic hydrogen-alpha, -beta, and -gamma lines show electron number densities of 0.3 to 4x10(17) cm(-3) for time delays of 2.1 to 0.4 micros after laser-induced optical breakdown. In methane flow, recombination molecular spectra of the Delta nu = +2 progression of the C(2) Swan system are discernable in the H(beta) and H(gamma) plasma emissions within the first few microseconds. The recorded atomic spectra indicate the occurrence of hydrogen self-absorption for pulsed CH(4) flow pressures of 2.7x10(5) Pa (25 psig) and 6.5x10(5) Pa (80 psig).
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Affiliation(s)
- Christian G Parigger
- The University of Tennessee Space Institute, 411 B. H. Goethert Parkway, Tullahoma, Tennessee 37388, USA.
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Nemes L, Keszler AM, Parigger CG, Hornkohl JO, Michelsen HA, Stakhursky V. Spontaneous emission from the C3 radical in carbon plasma. Appl Opt 2007; 46:4032-40. [PMID: 17571143 DOI: 10.1364/ao.46.004032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Spontaneous emission measurements are discussed for the Swings transitions of the C(3) radical in laser-generated graphite plasma, and the spectroscopy of the C(3) radical in carbon vapor and plasma is summarized. A review is given of some theoretical calculations and emission spectroscopic investigations are presented. Time-averaged, laser-induced optical breakdown spectra are reported from Nd:YAG laser generated graphite microplasma. In 200-300 Torr of argon and helium, and depending on the specific experimental configuration, a weak emission continuum is observed centered at 400 nm when using a laser fluence of typically 1 J/cm(2). Such continua were not detected in our previous experiments using focused laser radiation. The possibilities for the origin of this continuum are considered.
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Affiliation(s)
- László Nemes
- Laboratory for Laser Spectroscopy, Chemical Research Center of the Hungarian Academy of Sciences, Budapest, Hungary
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Abstract
We report time-averaged and time-resolved emission spectra subsequent to laser-induced optical breakdown of aluminum in laboratory air and in hydrogen gas. The microplasma generated by nominal 10 ns IR laser radiation shows Stark-broadened and shifted atomic lines. An analysis of the H(alpha) and H(beta) Balmer series lines and selected aluminum lines allows one to determine electron number density in the range of 0.01 - 10 x 10(18) cm(-3) early in the plasma decay. Atomic and molecular features are investigated for diagnostic applications in laser material processing.
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Nemes L, Keszler AM, Hornkohl JO, Parigger CG. Laser-induced carbon plasma emission spectroscopic measurements on solid targets and in gas-phase optical breakdown. Appl Opt 2005; 44:3661-7. [PMID: 15989040 DOI: 10.1364/ao.44.003661] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We report measurements of time- and spatially averaged spontaneous-emission spectra following laser-induced breakdown on a solid graphite/ambient gas interface and on solid graphite in vacuum, and also emission spectra from gas-phase optical breakdown in allene C3H4 and helium, and in CO2 and helium mixtures. These emission spectra were dominated by CII (singly ionized carbon), CIII (doubly ionized carbon), hydrogen Balmer beta (Hbeta), and Swan C2 band features. Using the local thermodynamic equilibrium and thin plasma assumptions, we derived electron number density and electron temperature estimates. The former was in the 10(16) cm(-3) range, while the latter was found to be near 20000 K. In addition, the vibration-rotation temperature of the Swan bands of the C2 radical was determined to be between 4500 and 7000 K, using an exact theoretical model for simulating diatomic emission spectra. This temperature range is probably caused by the spatial inhomogeneity of the laser-induced plasma plume. Differences are pointed out in the role of ambient CO2 in a solid graphite target and in gas-phase breakdown plasma.
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Affiliation(s)
- László Nemes
- Laboratory for Laser Spectroscopy, Chemical Research Center, Hungarian Academy of Sciences, Pusztaszeri ut 59-67, H-1025 Budapest, Hungary.
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Abstract
A new method is presented for computation of diatomic rotational line strengths, or Hönl-London factors. The traditional approach includes separately calculating line positions and Hönl-London factors and assigning parity labels. The present approach shows that one merely computes the line strength for all possible term differences and discards those differences for which the strength vanishes. Numerical diagonalization of the upper and lower Hamiltonians is used, which directly obtains the line positions, Hönl-London factors, total parities, and e/f parities for both heteronuclear and homonuclear diatomic molecules. The FORTRAN computer program discussed is also applicable for calculating n-photon diatomic spectra.
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Affiliation(s)
- James O Hornkohl
- The University of Tennessee Space Institute, 411 B. H. Goethert Parkway, Tullahoma, Tennessee 37388, USA.
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Parigger CG, Hornkohl JO, Keszler AM, Nemes L. Measurement and analysis of atomic and diatomic carbon spectra from laser ablation of graphite. Appl Opt 2003; 42:6192-6198. [PMID: 14594084 DOI: 10.1364/ao.42.006192] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Spectra from plasma produced by laser-induced breakdown of graphite were recorded and analyzed to increase our understanding of the way in which carbon nanoparticles are created during Nd:YAG laser ablation of graphite. The effects of various buffer gases were studied. Electron density and temperature were determined from spectra of the first and second ions of atomic carbon. The C2 Swan spectrum was also prominent in most of the measured spectra. Temperature was inferred from each experimental Swan spectrum by determination of the temperature for which a synthetic Swan spectrum best fitted, in the least-squares sense, the measured spectrum.
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Affiliation(s)
- Christian G Parigger
- Center for Laser Applications, The University of Tennessee Space Institute, 411 B. H. Goethert Parkway, Tullahoma, Tennessee 37388, USA.
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Abstract
Temperature and pressure profiles are computed by the use of a two-dimensional, axially symmetric, time-accurate computational fluid-dynamic model for nominal 10-ns optical breakdown laser pulses. The computational model includes a kinetics mechanism that implements plasma equilibrium kinetics in ionized regions and nonequilibrium, multistep, finite-rate reactions in nonionized regions. Fluid-physics phenomena following laser-induced breakdown are recorded with high-speed shadowgraph techniques. The predicted fluid phenomena are shown by direct comparison with experimental records to agree with the flow patterns that are characteristic of laser spark decay.
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Affiliation(s)
- Ivan G Dors
- Space Science Center, University of New Hampshire, 39 College Road, Durham, NH 03824, USA
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Parigger CG, Guan G, Hornkohl JO. Measurement and analysis of OH emission spectra following laser-induced optical breakdown in air. Appl Opt 2003; 42:5986-5991. [PMID: 14594055 DOI: 10.1364/ao.42.005986] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The measured emission spectra of the OH radical subsequent to laser-induced optical breakdown in air are analyzed to infer spectroscopic temperature and species number density. Emissions from the UV A2sigma+ --> X2IIi transition dominate the spectra in the wavelength range of 306-322 nm and for time delays from the optical breakdown of 30-300 micros. Contributions from other species to the recorded OH emission spectra were also investigated for spectroscopic temperature measurements in the range of 2000-6000 K and for OH number densities in the range of 10(14) - 2 x 10(16) cm(-3). Monte Carlo simulations are applied to estimate errors in the analysis of the hydroxyl spectra.
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Affiliation(s)
- Christian G Parigger
- Center for Laser Applications, The University of Tennessee Space Institute, 411 B. H. Goethert Parkway, Tullahoma, Tennessee 37388, USA
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Abstract
Stark-broadened emission profiles of the Balmer series Hbeta lines are measured subsequent to nanosecond laser-induced optical breakdown in gaseous hydrogen. Electron number densities are found from time-resolved spectra from Hbeta emissions to be in the range 10(15)-10(18) cm(-3). These results are compared with Halpha measurements for which number densities as high as 10(19) cm(-3) are determined from Stark widths and Stark shifts. Good agreement is reported for number densities inferred from Halpha and Hbeta emissions, down to an electron number density 3 x 10(16) cm(-3), by accurate treatment of ion dynamics in the theory.
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Affiliation(s)
- Christian G Parigger
- Center for Laser Applications, The University of Tennessee Space Institute, 411 B.H. Goethert Parkway, Tullahoma, Tennessee 37388, USA.
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