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Publications (9 of 9) Show all publications
Hjältén, A., Foltynowicz, A. & Sadiek, I. (2023). Line positions and intensities of the ν1 band of 12CH3I using mid-infrared optical frequency comb Fourier transform spectroscopy. Journal of Quantitative Spectroscopy and Radiative Transfer, 306, Article ID 108646.
Open this publication in new window or tab >>Line positions and intensities of the ν1 band of 12CH3I using mid-infrared optical frequency comb Fourier transform spectroscopy
2023 (English)In: Journal of Quantitative Spectroscopy and Radiative Transfer, ISSN 0022-4073, E-ISSN 1879-1352, Vol. 306, article id 108646Article in journal (Refereed) Published
Abstract [en]

We present a new spectral analysis of the ν1 and ν3+ν1−ν3 bands of 12CH3I around 2971 cm−1 based on a high-resolution spectrum spanning from 2800 cm–1 to 3160 cm–1, measured using an optical frequency comb Fourier transform spectrometer. From this spectrum, we previously assigned the ν4 and ν3+ν4−ν3 bands around 3060 cm–1 using PGOPHER, and the line list was incorporated in the HITRAN database. Here, we treat the two fundamental bands, ν1 and ν4, together with the perturbing states, 2ν2+ν3 and ν2+2ν6±2, as a four-level system connected via Coriolis and Fermi interactions. A similar four-level system is assumed to connect the two ν3+ν1−ν3 and ν3+ν4−ν3 hot bands, which appear due to the population of the low-lying ν3 state at room temperature, with the 2ν2+2ν3 and ν2+ν3+2ν6±2 perturbing states. This spectroscopic treatment provides a good global agreement of the simulated spectra with experiment, and hence accurate line lists and band parameters of the four connected vibrational states in each system. It also allows revisiting the analysis of the ν4 and ν3+ν4−ν3 bands, which were previously treated as separate bands, not connected to their ν1 and ν3+ν1−ν3 counterparts. Overall, we assign 4665 transitions in the fundamental band system, with an average error of 0.00071 cm–1, a factor of two better than earlier work on the ν1 band using conventional Fourier transform infrared spectroscopy. The ν1 band shows hyperfine splitting, resolvable for transitions with J ≤ 2 × K. Finally, the spectral intensities of 65 lines of the ν1 band and 7 lines of the ν3+ν1−ν3 band are reported for the first time using the Voigt line shape as a model in multispectral fitting. The reported line lists and intensities will serve as a reference for high-resolution molecular spectroscopic databases, and as a basis for line selection in future monitoring applications of CH3I.

Place, publisher, year, edition, pages
Elsevier, 2023
National Category
Atom and Molecular Physics and Optics Condensed Matter Physics
Identifiers
urn:nbn:se:umu:diva-209110 (URN)10.1016/j.jqsrt.2023.108646 (DOI)001007953500001 ()2-s2.0-85159161690 (Scopus ID)
Funder
Knut and Alice Wallenberg Foundation, 2015.0159Knut and Alice Wallenberg Foundation, 2020.0303Swedish Research Council, 2016-03593Swedish Research Council, 2020-00238
Available from: 2023-06-08 Created: 2023-06-08 Last updated: 2023-11-13Bibliographically approved
Sadiek, I., Hjältén, A., Roberts, F. C., Lehman, J. H. & Foltynowicz, A. (2023). Optical frequency comb-based measurements and the revisited assignment of high-resolution spectra of CH2Br2 in the 2960 to 3120 cm−1 region. Physical Chemistry, Chemical Physics - PCCP, 25, Article ID 8743.
Open this publication in new window or tab >>Optical frequency comb-based measurements and the revisited assignment of high-resolution spectra of CH2Br2 in the 2960 to 3120 cm−1 region
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2023 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 25, article id 8743Article in journal (Refereed) Published
Abstract [en]

Brominated organic compounds are toxic ocean-derived trace gases that affect the oxidation capacity of the atmosphere and contribute to its bromine burden. Quantitative spectroscopic detection of these gases is limited by the lack of accurate absorption cross-section data as well as rigorous spectroscopic models. This work presents measurements of high-resolution spectra of dibromomethane, CH2Br2, from 2960 cm−1 to 3120 cm−1 by two optical frequency comb-based methods, Fourier transform spectroscopy and a spatially dispersive method based on a virtually imaged phased array. The integrated absorption cross-sections measured using the two spectrometers are in excellent agreement with each other within 4%. A revisited rovibrational assignment of the measured spectra is introduced, in which the progressions of features are attributed to hot bands rather than different isotopologues as was previously done. Overall, twelve vibrational transitions, four for each of the three isotopologues CH281Br2, CH279Br81Br, and CH279Br2, are assigned. These four vibrational transitions are attributed to the fundamental ν6 band and the nearby nν4 + ν6 − nν4 hot bands (with n = 1–3) due to the population of the low-lying ν4 mode of the Br–C–Br bending vibration at room temperature. The new simulations show very good agreement in intensities with the experiment as predicted by the Boltzmann distribution factor. The spectra of the fundamental and the hot bands show progressions of strong QKa(J) rovibrational sub-clusters. The band heads of these sub-clusters are assigned and fitted to the measured spectra, providing accurate band origins and the rotational constants for the twelve states with an average error of 0.0084 cm−1. A detailed fit of the ν6 band of the CH279Br81Br isotopologue is commenced after assigning 1808 partially resolved rovibrational lines, with the band origin, rotational, and centrifugal constants as fit parameters, resulting in an average error of 0.0011 cm−1.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2023
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:umu:diva-206029 (URN)10.1039/d2cp05881b (DOI)000946509500001 ()2-s2.0-85150414323 (Scopus ID)
Funder
Knut and Alice Wallenberg Foundation, 2015.0159Knut and Alice Wallenberg Foundation, 2020.0303Swedish Research Council, 2016-03593Swedish Research Council, 2020-00238Swedish Research Council, 2018-05973Swedish National Infrastructure for Computing (SNIC)
Available from: 2023-03-28 Created: 2023-03-28 Last updated: 2023-11-10Bibliographically approved
Sadiek, I., Hjältén, A., Vieira, F. S., Lu, C., Stuhr, M. & Foltynowicz, A. (2020). Line positions and intensities of the ν4 band of methyl iodide using mid-infrared optical frequency comb Fourier transform spectroscopy. Journal of Quantitative Spectroscopy and Radiative Transfer, 255, Article ID 107263.
Open this publication in new window or tab >>Line positions and intensities of the ν4 band of methyl iodide using mid-infrared optical frequency comb Fourier transform spectroscopy
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2020 (English)In: Journal of Quantitative Spectroscopy and Radiative Transfer, ISSN 0022-4073, E-ISSN 1879-1352, Vol. 255, article id 107263Article in journal (Refereed) Published
Abstract [en]

We use optical frequency comb Fourier transform spectroscopy to measure high-resolution spectra of iodomethane, CH3I, in the C-H stretch region from 2800 to 3160 cm(-1). The fast-scanning Fourier transform spectrometer with auto-balanced detection is based on a difference frequency generation comb with repetition rate, f(rep), of 125 MHz. A series of spectra with sample point spacing equal to f rep are measured at different f rep settings and interleaved to yield sampling point spacing of 11 MHz. Iodomethane is introduced into a 76 m long multipass absorption cell by its vapor pressure at room temperature. The measured spectrum contains three main ro-vibrational features: the parallel vibrational overtone and combination bands centered around 2850 cm(-1), the symmetric stretch nu(1) band centered at 2971 cm(-1), and the asymmetric stretch nu(4) band centered at 3060 cm(-1). The spectra of the nu(4) band and the nearby nu(3)+nu(4)-nu(3) hot band are simulated using PGOPHER and a new assignment of these bands is presented. The resolved ro-vibrational structures are used in a least square fit together with the microwave data to provide the upper state parameters. We assign 2603 transitions to the nu(4) band with a standard deviation (observed - calculated) of 0.00034 cm(-1), and 831 transitions to the nu(3)+nu(4)-nu(3) hot band with a standard deviation of 0.00084 cm(-1). For comparison, in the earlier work using standard FT-IR with 162 MHz resolution [Anttila, et al., J. Mol. Spectrosc. 1986; 119:190-200] 1830 transition were assigned to the nu(4) band, and 380 transitions to the nu(3)+nu(4)-nu(3) hot band, with standard deviations of 0.00083 cm(-1) and 0.0013 cm(-1), respectively. The hyperfine splittings due to the 127 I nuclear quadrupole moment are observed for transitions with J <= 2 x K. Finally, intensities of 157 isolated transitions in the nu(4) band are reported for the first time using the Voigt line shape as a model in multispectral fitting.

Place, publisher, year, edition, pages
Elsevier, 2020
Keywords
Methyl iodide, High-resolution spectroscopy, Optical frequency comb, Fourier transform spectroscopy
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:umu:diva-176794 (URN)10.1016/j.jqsrt.2020.107263 (DOI)000581971300031 ()2-s2.0-85090048420 (Scopus ID)
Available from: 2020-11-25 Created: 2020-11-25 Last updated: 2023-11-10Bibliographically approved
Sadiek, I., Hjältén, A., Stuhr, M., Lu, C., Vieira, F. S. & Foltynowicz, A. (2020). Mid-infrared comb-based fourier transform spectroscopy of halogenated volatile organic compounds. In: 2020 Conference on Lasers and Electro-Optics (CLEO): . Paper presented at Conference on Lasers and Electro-Optics (CLEO), MAY 10-15, 2020, San Jose, CA, USA. IEEE, Article ID 9192281.
Open this publication in new window or tab >>Mid-infrared comb-based fourier transform spectroscopy of halogenated volatile organic compounds
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2020 (English)In: 2020 Conference on Lasers and Electro-Optics (CLEO), IEEE, 2020, article id 9192281Conference paper, Published paper (Refereed)
Abstract [en]

Broadband high-resolution spectra of two key atmospheric species, methyl iodide (CH3I) and dibromomethane (CH2Br2), are measured around 3 µm using a comb-based Fourier transform spectrometer and assigned with the help of the semi-automatic fitting in PGOPHER. 

Place, publisher, year, edition, pages
IEEE, 2020
Series
Conference on Lasers and Electro-Optics, ISSN 2160-9020
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:umu:diva-187149 (URN)000612090000306 ()2-s2.0-85091674362 (Scopus ID)978-1-943580-76-7 (ISBN)978-1-7281-4418-4 (ISBN)
Conference
Conference on Lasers and Electro-Optics (CLEO), MAY 10-15, 2020, San Jose, CA, USA
Funder
Swedish Research Council, 2016-03593Knut and Alice Wallenberg Foundation, KAW 2015.0159
Note

Also published in Optics InfoBase Conference Papers, ISSN: 2162-2701.

Available from: 2021-09-13 Created: 2021-09-13 Last updated: 2023-09-04Bibliographically approved
Sadiek, I., Hjältén, A., Stuhr, M., Friedrichs, G. & Foltynowicz, A. (2020). Towards a Transferable Standard for Nitrous Oxide Isotopomer Ratio. In: 2020 Conference on Lasers and Electro-Optics (CLEO): . Paper presented at Conference on Lasers and Electro-Optics (CLEO), MAY 10-15, 2020, San Jose, CA, USA. IEEE, Article ID 9192530.
Open this publication in new window or tab >>Towards a Transferable Standard for Nitrous Oxide Isotopomer Ratio
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2020 (English)In: 2020 Conference on Lasers and Electro-Optics (CLEO), IEEE, 2020, article id 9192530Conference paper, Published paper (Refereed)
Abstract [en]

We report a novel approach for identifying the 15N site-preference in N2O from a chemical reaction using continuous wave cavity ringdown spectroscopy and comb-based Fourier transform spectroscopy, with the aim to establish the currently lacking international N2O isotopomer standard. 

Place, publisher, year, edition, pages
IEEE, 2020
Series
Conference on Lasers and Electro-Optics, ISSN 2160-9020
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:umu:diva-187148 (URN)000612090001024 ()2-s2.0-85091646934 (Scopus ID)978-1-943580-76-7 (ISBN)978-1-7281-4418-4 (ISBN)
Conference
Conference on Lasers and Electro-Optics (CLEO), MAY 10-15, 2020, San Jose, CA, USA
Funder
Knut and Alice Wallenberg Foundation, KAW 2015.0159Swedish Research Council, 2016-03593
Available from: 2021-09-13 Created: 2021-09-13 Last updated: 2021-09-13Bibliographically approved
Sadiek, I., Hjältén, A., Stuhr, M., Friedrichs, G. & Foltynowicz, A. (2020). Towards a transferable standard for nitrous oxide isotopomer ratio. In: Conference on Lasers and Electro-Optics: . Paper presented at CLEO: Science and Innovations, CLEO_SI 2020, Washington, DC United States, 10–15 May 2020.. Optica Publishing Group (formerly OSA), Article ID STu4N.4.
Open this publication in new window or tab >>Towards a transferable standard for nitrous oxide isotopomer ratio
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2020 (English)In: Conference on Lasers and Electro-Optics, Optica Publishing Group (formerly OSA) , 2020, article id STu4N.4Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

We report a novel approach for identifying the 15N site-preference in N2O from a chemical reaction using continuous wave cavity ringdown spectroscopy and comb-based Fourier transform spectroscopy, with the aim to establish the currently lacking international N2O isotopomer standard.

Place, publisher, year, edition, pages
Optica Publishing Group (formerly OSA), 2020
Series
Optics InfoBase Conference Papers, E-ISSN 21622701
National Category
Atom and Molecular Physics and Optics Other Physics Topics
Identifiers
urn:nbn:se:umu:diva-212629 (URN)10.1364/CLEO_SI.2020.STu4N.4 (DOI)2-s2.0-85095435392 (Scopus ID)9781943580767 (ISBN)
Conference
CLEO: Science and Innovations, CLEO_SI 2020, Washington, DC United States, 10–15 May 2020.
Available from: 2023-09-04 Created: 2023-09-04 Last updated: 2023-09-04Bibliographically approved
Sadiek, I., Mikkonen, T., Vainio, M., Toivonen, J. & Foltynowicz, A. (2019). Optical Frequency Comb Photoacoustic Spectroscopy. In: Conference on Lasers and Electro-Optics: . Paper presented at Conference on Lasers and Electro-Optics (CLEO), San Jose, California, United States, 5-10 May, 2019. IEEE, Article ID SW3L.5.
Open this publication in new window or tab >>Optical Frequency Comb Photoacoustic Spectroscopy
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2019 (English)In: Conference on Lasers and Electro-Optics, IEEE, 2019, article id SW3L.5Conference paper, Published paper (Refereed)
Abstract [en]

We combine for the first time a mid-infrared optical frequency comb Fourier transform spectrometer with cantilever-enhanced photoacoustic detection and measure high-resolution broadband spectra of the fundamental band of methane in a few milliliter sample volume.

Place, publisher, year, edition, pages
IEEE, 2019
Series
Conference on Lasers and Electro-Optics, ISSN 2160-9020
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:umu:diva-163710 (URN)10.1364/CLEO_SI.2019.SW3L.5 (DOI)000482226301156 ()2-s2.0-85068148158 (Scopus ID)978-1-943580-57-6 (ISBN)
Conference
Conference on Lasers and Electro-Optics (CLEO), San Jose, California, United States, 5-10 May, 2019
Available from: 2019-10-16 Created: 2019-10-16 Last updated: 2019-10-16Bibliographically approved
Sadiek, I., Mikkonen, T., Vainio, M., Toivonen, J. & Foltynowicz, A. (2019). Optical frequency comb photoacoustic spectroscopy. In: 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC): . Paper presented at 2019 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2019, Munich, Germany, June 23-27, 2019. IEEE
Open this publication in new window or tab >>Optical frequency comb photoacoustic spectroscopy
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2019 (English)In: 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), IEEE, 2019Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Photoacoustic spectroscopy (PAS) based on continuous wave (cw) lasers provides high absorption sensitivity in small sample volume [1, 2] but it is usually restricted to single species detection because of the limited tunability of cw lasers. Broadband PAS has been demonstrated using cantilever-enhanced detectors in combination with incoherent [3] or supercontinuum [4] light sources modulated by conventional Fourier transform spectrometers (FTS), however, the spectral resolution was limited to a few cm-1. Here we report the first demonstration of optical frequency comb photoacoustic spectroscopy (OFC-PAS), which combines the wide spectral coverage and high resolution of frequency combs with the small sample volume of photoacoustic detection [5].

Place, publisher, year, edition, pages
IEEE, 2019
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:umu:diva-215281 (URN)10.1109/CLEOE-EQEC.2019.8872436 (DOI)2-s2.0-85074636057 (Scopus ID)9781728104690 (ISBN)
Conference
2019 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2019, Munich, Germany, June 23-27, 2019
Funder
Knut and Alice Wallenberg Foundation, 2015.0159
Available from: 2023-10-17 Created: 2023-10-17 Last updated: 2023-10-17Bibliographically approved
Sadiek, I., Mikkonen, T., Vainio, M., Toivonen, J. & Foltynowicz, A. (2018). Optical frequency comb photoacoustic spectroscopy. Physical Chemistry, Chemical Physics - PCCP, 20(44), 27849-27855
Open this publication in new window or tab >>Optical frequency comb photoacoustic spectroscopy
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2018 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, no 44, p. 27849-27855Article in journal (Refereed) Published
Abstract [en]

We report the first photoacoustic detection scheme using an optical frequency comb—optical frequency comb photoacoustic spectroscopy (OFC-PAS). OFC-PAS combines the broad spectral coverage and the high resolution of OFCs with the small sample volume of cantilever-enhanced PA detection. In OFC-PAS, a Fourier transform spectrometer (FTS) is used to modulate the intensity of the exciting comb source at a frequency determined by its scanning speed. One of the FTS outputs is directed to the PA cell and the other is measured simultaneously with a photodiode and used to normalize the PA signal. The cantilever-enhanced PA detector operates in a non-resonant mode, enabling detection of a broadband frequency response. The broadband and the high-resolution capabilities of OFC-PAS are demonstrated by measuring the rovibrational spectra of the fundamental C–H stretch band of CH4, with no instrumental line shape distortions, at total pressures of 1000 mbar, 650 mbar, and 400 mbar. In this first demonstration, a spectral resolution two orders of magnitude better than previously reported with broadband PAS is obtained, limited by the pressure broadening. A limit of detection of 0.8 ppm of methane in N2 is accomplished in a single interferogram measurement (200 s measurement time, 1000 MHz spectral resolution, 1000 mbar total pressure) for an exciting power spectral density of 42 μW/cm−1. A normalized noise equivalent absorption of 8 × 10−10 W cm−1 Hz−1/2 is obtained, which is only a factor of three higher than the best reported with PAS based on continuous wave lasers. A wide dynamic range of up to four orders of magnitude and a very good linearity (limited by the Beer–Lambert law) over two orders of magnitude are realized. OFC-PAS extends the capability of optical sensors for multispecies trace gas analysis in small sample volumes with high resolution and selectivity.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2018
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:umu:diva-154040 (URN)10.1039/c8cp05666h (DOI)000450660400011 ()30398249 (PubMedID)2-s2.0-85056520950 (Scopus ID)
Funder
Knut and Alice Wallenberg Foundation, KAW 2015.0159
Available from: 2018-12-19 Created: 2018-12-19 Last updated: 2023-03-24Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-8082-5229

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