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Jos Oomens - One of the best experts on this subject based on the ideXlab platform.
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high resolution IR Absorption spectroscopy of polycyclic aromatic hydrocarbons in the 3 μm region role of periphery
The Astrophysical Journal, 2016Co-Authors: Elena Maltseva, Annemieke Petrignani, Alessandra Candian, Cameron J Mackie, Xinchuan Huang, Timothy J Lee, A G G M Tielens, Jos OomensAbstract:In this work we report on high-resolution IR Absorption studies that provide a detailed view on how the peripheral structure of IRregular polycyclic aromatic hydrocarbons (PAHs) affects the shape and position of theIR 3-micrometers Absorption band. To this purpose we present mass-selected, high-resolution Absorption spectra of cold and isolated phenanthrene, pyrene, benz[a]antracene, chrysene, triphenylene, and perylene molecules in the 2950-3150 per cm range. The experimental spectra are compared with standard harmonic calculations, and anharmonic calculations using a modified version of the SPECTRO program that incorporates a Fermi resonance treatment utilizing intensity redistribution. We show that the 3-micrometers region is dominated by the effects of anharmonicity, resulting in many more bands than would have been expected in a purely harmonic approximation. Importantly, we find that anharmonic spectra as calculated by SPECTRO are in good agreement with the experimental spectra. Together with previously reported high-resolution spectra of linear acenes, the present spectra provide us with an extensive dataset of spectra of PAHs with a varying number of aromatic rings, with geometries that range from open to highly-condensed structures, and featuring CH groups in all possible edge configurations. We discuss the astrophysical implications of the comparison of these spectra on the interpretation of the appearance of the aromatic infrared 3-micrometers band, and on features such as the two-component emission character of this band and the 3-micrometers emission plateau.
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high resolution IR Absorption spectroscopy of polycyclic aromatic hydrocarbons the realm of anharmonicity
The Astrophysical Journal, 2015Co-Authors: Elena Maltseva, Annemieke Petrignani, Alessandra Candian, Cameron J Mackie, Xinchuan Huang, Timothy J Lee, A G G M Tielens, Jos Oomens, Wybren Jan BumaAbstract:We report on an experimental and theoretical investigation of the importance of anharmonicity in the 3 micrometers CH stretching region of Polycyclic Aromatic Hydrocarbon (PAH) molecules. We present mass-resolved, high-resolution spectra of the gas-phase cold ((is) approximately 4K) linear PAH molecules naphthalene, anthracene, and tetracene. The measured IR spectra show a surprisingly high number of strong vibrational bands. For naphthalene, the observed bands are well separated and limited by the rotational contour, revealing the band symmetries. Comparisons are made to the harmonic and anharmonic approaches of the widely used Gaussian software. We also present calculated spectra of these acenes using the computational program SPECTRO, providing anharmonic predictions enhanced with a Fermi-resonance treatment that utilizes intensity redistribution. We demonstrate that the anharmonicity of the investigated acenes is strong, dominated by Fermi resonances between the fundamental and double combination modes, with triple combination bands as possible candidates to resolve remaining discrepancies. The anharmonic spectra as calculated with SPECTRO lead to predictions of the main modes that fall within 0.5% of the experimental frequencies. The implications for the Aromatic Infrared Bands, specifically the 3-m band are discussed.
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high resolution IR Absorption spectroscopy of polycyclic aromatic hydrocarbons the realm of anharmonicity
arXiv: Astrophysics of Galaxies, 2015Co-Authors: Elena Maltseva, Annemieke Petrignani, Alessandra Candian, Cameron J Mackie, Xinchuan Huang, Timothy J Lee, A G G M Tielens, Jos Oomens, Wybren Jan BumaAbstract:We report on an experimental and theoretical investigation of the importance of anharmonicity in the 3 micron CH stretching region of Polycyclic Aromatic Hydrocarbon (PAH) molecules. We present mass-resolved, high-resolution spectra of the gas-phase cold (~4K) linear PAH molecules naphthalene, anthracene, and tetracene. The measured IR spectra show a surprisingly high number of strong vibrational bands. For naphthalene, the observed bands are well separated and limited by the rotational contour, revealing the band symmetries. Comparisons are made to the harmonic and anharmonic approaches of the widely used Gaussian software. We also present calculated spectra of these acenes using the computational program SPECTRO, providing anharmonic predictions enhanced with a Fermi-resonance treatment that utilises intensity redistribution. We demonstrate that the anharmonicity of the investigated acenes is strong, dominated by Fermi resonances between the fundamental and double combination modes, with triple combination bands as possible candidates to resolve remaining discrepancies. The anharmonic spectra as calculated with SPECTRO lead to predictions of the main modes that fall within 0.5% of the experimental frequencies. The implications for the Aromatic Infrared Bands, specifically the 3 micron band are discussed.
Xinchuan Huang - One of the best experts on this subject based on the ideXlab platform.
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high resolution IR Absorption spectroscopy of polycyclic aromatic hydrocarbons in the 3 μm region role of periphery
The Astrophysical Journal, 2016Co-Authors: Elena Maltseva, Annemieke Petrignani, Alessandra Candian, Cameron J Mackie, Xinchuan Huang, Timothy J Lee, A G G M Tielens, Jos OomensAbstract:In this work we report on high-resolution IR Absorption studies that provide a detailed view on how the peripheral structure of IRregular polycyclic aromatic hydrocarbons (PAHs) affects the shape and position of theIR 3-micrometers Absorption band. To this purpose we present mass-selected, high-resolution Absorption spectra of cold and isolated phenanthrene, pyrene, benz[a]antracene, chrysene, triphenylene, and perylene molecules in the 2950-3150 per cm range. The experimental spectra are compared with standard harmonic calculations, and anharmonic calculations using a modified version of the SPECTRO program that incorporates a Fermi resonance treatment utilizing intensity redistribution. We show that the 3-micrometers region is dominated by the effects of anharmonicity, resulting in many more bands than would have been expected in a purely harmonic approximation. Importantly, we find that anharmonic spectra as calculated by SPECTRO are in good agreement with the experimental spectra. Together with previously reported high-resolution spectra of linear acenes, the present spectra provide us with an extensive dataset of spectra of PAHs with a varying number of aromatic rings, with geometries that range from open to highly-condensed structures, and featuring CH groups in all possible edge configurations. We discuss the astrophysical implications of the comparison of these spectra on the interpretation of the appearance of the aromatic infrared 3-micrometers band, and on features such as the two-component emission character of this band and the 3-micrometers emission plateau.
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high resolution IR Absorption spectroscopy of polycyclic aromatic hydrocarbons the realm of anharmonicity
The Astrophysical Journal, 2015Co-Authors: Elena Maltseva, Annemieke Petrignani, Alessandra Candian, Cameron J Mackie, Xinchuan Huang, Timothy J Lee, A G G M Tielens, Jos Oomens, Wybren Jan BumaAbstract:We report on an experimental and theoretical investigation of the importance of anharmonicity in the 3 micrometers CH stretching region of Polycyclic Aromatic Hydrocarbon (PAH) molecules. We present mass-resolved, high-resolution spectra of the gas-phase cold ((is) approximately 4K) linear PAH molecules naphthalene, anthracene, and tetracene. The measured IR spectra show a surprisingly high number of strong vibrational bands. For naphthalene, the observed bands are well separated and limited by the rotational contour, revealing the band symmetries. Comparisons are made to the harmonic and anharmonic approaches of the widely used Gaussian software. We also present calculated spectra of these acenes using the computational program SPECTRO, providing anharmonic predictions enhanced with a Fermi-resonance treatment that utilizes intensity redistribution. We demonstrate that the anharmonicity of the investigated acenes is strong, dominated by Fermi resonances between the fundamental and double combination modes, with triple combination bands as possible candidates to resolve remaining discrepancies. The anharmonic spectra as calculated with SPECTRO lead to predictions of the main modes that fall within 0.5% of the experimental frequencies. The implications for the Aromatic Infrared Bands, specifically the 3-m band are discussed.
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high resolution IR Absorption spectroscopy of polycyclic aromatic hydrocarbons the realm of anharmonicity
arXiv: Astrophysics of Galaxies, 2015Co-Authors: Elena Maltseva, Annemieke Petrignani, Alessandra Candian, Cameron J Mackie, Xinchuan Huang, Timothy J Lee, A G G M Tielens, Jos Oomens, Wybren Jan BumaAbstract:We report on an experimental and theoretical investigation of the importance of anharmonicity in the 3 micron CH stretching region of Polycyclic Aromatic Hydrocarbon (PAH) molecules. We present mass-resolved, high-resolution spectra of the gas-phase cold (~4K) linear PAH molecules naphthalene, anthracene, and tetracene. The measured IR spectra show a surprisingly high number of strong vibrational bands. For naphthalene, the observed bands are well separated and limited by the rotational contour, revealing the band symmetries. Comparisons are made to the harmonic and anharmonic approaches of the widely used Gaussian software. We also present calculated spectra of these acenes using the computational program SPECTRO, providing anharmonic predictions enhanced with a Fermi-resonance treatment that utilises intensity redistribution. We demonstrate that the anharmonicity of the investigated acenes is strong, dominated by Fermi resonances between the fundamental and double combination modes, with triple combination bands as possible candidates to resolve remaining discrepancies. The anharmonic spectra as calculated with SPECTRO lead to predictions of the main modes that fall within 0.5% of the experimental frequencies. The implications for the Aromatic Infrared Bands, specifically the 3 micron band are discussed.
Annemieke Petrignani - One of the best experts on this subject based on the ideXlab platform.
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high resolution IR Absorption spectroscopy of polycyclic aromatic hydrocarbons in the 3 μm region role of periphery
The Astrophysical Journal, 2016Co-Authors: Elena Maltseva, Annemieke Petrignani, Alessandra Candian, Cameron J Mackie, Xinchuan Huang, Timothy J Lee, A G G M Tielens, Jos OomensAbstract:In this work we report on high-resolution IR Absorption studies that provide a detailed view on how the peripheral structure of IRregular polycyclic aromatic hydrocarbons (PAHs) affects the shape and position of theIR 3-micrometers Absorption band. To this purpose we present mass-selected, high-resolution Absorption spectra of cold and isolated phenanthrene, pyrene, benz[a]antracene, chrysene, triphenylene, and perylene molecules in the 2950-3150 per cm range. The experimental spectra are compared with standard harmonic calculations, and anharmonic calculations using a modified version of the SPECTRO program that incorporates a Fermi resonance treatment utilizing intensity redistribution. We show that the 3-micrometers region is dominated by the effects of anharmonicity, resulting in many more bands than would have been expected in a purely harmonic approximation. Importantly, we find that anharmonic spectra as calculated by SPECTRO are in good agreement with the experimental spectra. Together with previously reported high-resolution spectra of linear acenes, the present spectra provide us with an extensive dataset of spectra of PAHs with a varying number of aromatic rings, with geometries that range from open to highly-condensed structures, and featuring CH groups in all possible edge configurations. We discuss the astrophysical implications of the comparison of these spectra on the interpretation of the appearance of the aromatic infrared 3-micrometers band, and on features such as the two-component emission character of this band and the 3-micrometers emission plateau.
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high resolution IR Absorption spectroscopy of polycyclic aromatic hydrocarbons the realm of anharmonicity
The Astrophysical Journal, 2015Co-Authors: Elena Maltseva, Annemieke Petrignani, Alessandra Candian, Cameron J Mackie, Xinchuan Huang, Timothy J Lee, A G G M Tielens, Jos Oomens, Wybren Jan BumaAbstract:We report on an experimental and theoretical investigation of the importance of anharmonicity in the 3 micrometers CH stretching region of Polycyclic Aromatic Hydrocarbon (PAH) molecules. We present mass-resolved, high-resolution spectra of the gas-phase cold ((is) approximately 4K) linear PAH molecules naphthalene, anthracene, and tetracene. The measured IR spectra show a surprisingly high number of strong vibrational bands. For naphthalene, the observed bands are well separated and limited by the rotational contour, revealing the band symmetries. Comparisons are made to the harmonic and anharmonic approaches of the widely used Gaussian software. We also present calculated spectra of these acenes using the computational program SPECTRO, providing anharmonic predictions enhanced with a Fermi-resonance treatment that utilizes intensity redistribution. We demonstrate that the anharmonicity of the investigated acenes is strong, dominated by Fermi resonances between the fundamental and double combination modes, with triple combination bands as possible candidates to resolve remaining discrepancies. The anharmonic spectra as calculated with SPECTRO lead to predictions of the main modes that fall within 0.5% of the experimental frequencies. The implications for the Aromatic Infrared Bands, specifically the 3-m band are discussed.
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high resolution IR Absorption spectroscopy of polycyclic aromatic hydrocarbons the realm of anharmonicity
arXiv: Astrophysics of Galaxies, 2015Co-Authors: Elena Maltseva, Annemieke Petrignani, Alessandra Candian, Cameron J Mackie, Xinchuan Huang, Timothy J Lee, A G G M Tielens, Jos Oomens, Wybren Jan BumaAbstract:We report on an experimental and theoretical investigation of the importance of anharmonicity in the 3 micron CH stretching region of Polycyclic Aromatic Hydrocarbon (PAH) molecules. We present mass-resolved, high-resolution spectra of the gas-phase cold (~4K) linear PAH molecules naphthalene, anthracene, and tetracene. The measured IR spectra show a surprisingly high number of strong vibrational bands. For naphthalene, the observed bands are well separated and limited by the rotational contour, revealing the band symmetries. Comparisons are made to the harmonic and anharmonic approaches of the widely used Gaussian software. We also present calculated spectra of these acenes using the computational program SPECTRO, providing anharmonic predictions enhanced with a Fermi-resonance treatment that utilises intensity redistribution. We demonstrate that the anharmonicity of the investigated acenes is strong, dominated by Fermi resonances between the fundamental and double combination modes, with triple combination bands as possible candidates to resolve remaining discrepancies. The anharmonic spectra as calculated with SPECTRO lead to predictions of the main modes that fall within 0.5% of the experimental frequencies. The implications for the Aromatic Infrared Bands, specifically the 3 micron band are discussed.
Elena Maltseva - One of the best experts on this subject based on the ideXlab platform.
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high resolution IR Absorption spectroscopy of polycyclic aromatic hydrocarbons in the 3 μm region role of periphery
The Astrophysical Journal, 2016Co-Authors: Elena Maltseva, Annemieke Petrignani, Alessandra Candian, Cameron J Mackie, Xinchuan Huang, Timothy J Lee, A G G M Tielens, Jos OomensAbstract:In this work we report on high-resolution IR Absorption studies that provide a detailed view on how the peripheral structure of IRregular polycyclic aromatic hydrocarbons (PAHs) affects the shape and position of theIR 3-micrometers Absorption band. To this purpose we present mass-selected, high-resolution Absorption spectra of cold and isolated phenanthrene, pyrene, benz[a]antracene, chrysene, triphenylene, and perylene molecules in the 2950-3150 per cm range. The experimental spectra are compared with standard harmonic calculations, and anharmonic calculations using a modified version of the SPECTRO program that incorporates a Fermi resonance treatment utilizing intensity redistribution. We show that the 3-micrometers region is dominated by the effects of anharmonicity, resulting in many more bands than would have been expected in a purely harmonic approximation. Importantly, we find that anharmonic spectra as calculated by SPECTRO are in good agreement with the experimental spectra. Together with previously reported high-resolution spectra of linear acenes, the present spectra provide us with an extensive dataset of spectra of PAHs with a varying number of aromatic rings, with geometries that range from open to highly-condensed structures, and featuring CH groups in all possible edge configurations. We discuss the astrophysical implications of the comparison of these spectra on the interpretation of the appearance of the aromatic infrared 3-micrometers band, and on features such as the two-component emission character of this band and the 3-micrometers emission plateau.
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high resolution IR Absorption spectroscopy of polycyclic aromatic hydrocarbons the realm of anharmonicity
The Astrophysical Journal, 2015Co-Authors: Elena Maltseva, Annemieke Petrignani, Alessandra Candian, Cameron J Mackie, Xinchuan Huang, Timothy J Lee, A G G M Tielens, Jos Oomens, Wybren Jan BumaAbstract:We report on an experimental and theoretical investigation of the importance of anharmonicity in the 3 micrometers CH stretching region of Polycyclic Aromatic Hydrocarbon (PAH) molecules. We present mass-resolved, high-resolution spectra of the gas-phase cold ((is) approximately 4K) linear PAH molecules naphthalene, anthracene, and tetracene. The measured IR spectra show a surprisingly high number of strong vibrational bands. For naphthalene, the observed bands are well separated and limited by the rotational contour, revealing the band symmetries. Comparisons are made to the harmonic and anharmonic approaches of the widely used Gaussian software. We also present calculated spectra of these acenes using the computational program SPECTRO, providing anharmonic predictions enhanced with a Fermi-resonance treatment that utilizes intensity redistribution. We demonstrate that the anharmonicity of the investigated acenes is strong, dominated by Fermi resonances between the fundamental and double combination modes, with triple combination bands as possible candidates to resolve remaining discrepancies. The anharmonic spectra as calculated with SPECTRO lead to predictions of the main modes that fall within 0.5% of the experimental frequencies. The implications for the Aromatic Infrared Bands, specifically the 3-m band are discussed.
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high resolution IR Absorption spectroscopy of polycyclic aromatic hydrocarbons the realm of anharmonicity
arXiv: Astrophysics of Galaxies, 2015Co-Authors: Elena Maltseva, Annemieke Petrignani, Alessandra Candian, Cameron J Mackie, Xinchuan Huang, Timothy J Lee, A G G M Tielens, Jos Oomens, Wybren Jan BumaAbstract:We report on an experimental and theoretical investigation of the importance of anharmonicity in the 3 micron CH stretching region of Polycyclic Aromatic Hydrocarbon (PAH) molecules. We present mass-resolved, high-resolution spectra of the gas-phase cold (~4K) linear PAH molecules naphthalene, anthracene, and tetracene. The measured IR spectra show a surprisingly high number of strong vibrational bands. For naphthalene, the observed bands are well separated and limited by the rotational contour, revealing the band symmetries. Comparisons are made to the harmonic and anharmonic approaches of the widely used Gaussian software. We also present calculated spectra of these acenes using the computational program SPECTRO, providing anharmonic predictions enhanced with a Fermi-resonance treatment that utilises intensity redistribution. We demonstrate that the anharmonicity of the investigated acenes is strong, dominated by Fermi resonances between the fundamental and double combination modes, with triple combination bands as possible candidates to resolve remaining discrepancies. The anharmonic spectra as calculated with SPECTRO lead to predictions of the main modes that fall within 0.5% of the experimental frequencies. The implications for the Aromatic Infrared Bands, specifically the 3 micron band are discussed.
W Beyer - One of the best experts on this subject based on the ideXlab platform.
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a comparative analysis of a c h by infrared spectroscopy and mass selected thermal effusion
Journal of Applied Physics, 1998Co-Authors: J Ristein, R T Stief, L Ley, W BeyerAbstract:A comparative analysis of quantitative infrared Absorption spectra and mass selected thermal effusion transients measured for a large number of hydrogenated amorphous carbon (a-C:H) films is presented in order to establish reliable IR Absorption cross sections for the different hydrogen bonding configurations in the material. The structural character of the material and the hydrogen concentration were varied over a wide range from soft and wide band gap polymerlike a-C:H, via so-called diamondlike carbon, to the tetrahedral form of a-C:H deposited from a plasma beam source. The results show that the IR Absorption cross sections from molecular hydrocarbons can well be transferred to the solid state as long as the material is of polymeric character, but that this procedure fails as soon as the material converts into a three-dimensional cross-linked and mechanically hard structure. For the latter material an empIRical average IR Absorption cross section for the C–H stretch band can nevertheless be determined...
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a comparative analysis of a c h by infrared spectroscopy and mass selected thermal effusion
Journal of Applied Physics, 1998Co-Authors: J Ristein, R T Stief, L Ley, W BeyerAbstract:A comparative analysis of quantitative infrared Absorption spectra and mass selected thermal effusion transients measured for a large number of hydrogenated amorphous carbon (a-C:H) films is presented in order to establish reliable IR Absorption cross sections for the different hydrogen bonding configurations in the material. The structural character of the material and the hydrogen concentration were varied over a wide range from soft and wide band gap polymerlike a-C:H, via so-called diamondlike carbon, to the tetrahedral form of a-C:H deposited from a plasma beam source. The results show that the IR Absorption cross sections from molecular hydrocarbons can well be transferred to the solid state as long as the material is of polymeric character, but that this procedure fails as soon as the material converts into a three-dimensional cross-linked and mechanically hard structure. For the latter material an empIRical average IR Absorption cross section for the C–H stretch band can nevertheless be determined from a comparison between hydrogen effusion and IR spectra.
