Sequential Reactions of Acetylene with the Benzonitrile Radical Cation: New Insights into Structures and Rate Coefficients of the Covalent Ion Products DOI Creative Commons

Paul W. Sutton,

John Saunier, Ka Un Lao

et al.

The Journal of Physical Chemistry Letters, Journal Year: 2024, Volume and Issue: 15(44), P. 11067 - 11076

Published: Oct. 29, 2024

Benzonitrile radical cations generated in ionizing environments such as solar nebulae and interstellar clouds can react with neutral molecules acetylene to form a variety of nitrogen-containing complex organics. Herein, we present results from mass-selected ion mobility experiments coupled-cluster DFT calculations for the sequential reactions benzonitrile cation (C

Language: Английский

CN stretches around 4.4 microns dominate the IR absorption spectra of cyano-polycyclic aromatic hydrocarbons DOI Creative Commons
Vincent J. Esposito, Ryan C. Fortenberry, C. Boersma

et al.

Monthly Notices of the Royal Astronomical Society Letters, Journal Year: 2024, Volume and Issue: 531(1), P. L87 - L93

Published: March 29, 2024

ABSTRACT Anharmonic quantum chemical computations reveal a strong, narrow (width = 0.075 $\mu$m) band in the 4.3–4.5 $\mu$m region of absorption spectra cyano-substituted polycyclic aromatic hydrocarbons (CN-PAHs) cyanonaphthalene, cyanoanthracene, cyanophenanthrene, and cyanopyrene. This window with intense IR lines implies that CN-PAHs various shapes sizes offer little variation both wavelength intensity this region. Subsequently, can be used as tracer for CN-PAHs. The distinct features making up are assigned to mixed vibrational states consisting CN stretch fundamental combination bands, including in-plane CH bends, CC skeletal breathing motions. extraordinarily large intrinsic is redistributed nearby via anharmonic coupling, which readily captured when using second order perturbation theory resonance polyad matrices. redistribution leads complex spectrum. bands may contribute baseline continuum undulating macroscopic structure seen recent JWST NIRSpec observations.

Language: Английский

Citations

17
Pinpointing the CN Stretch Frequency of Neutral Cyano-Polycyclic Aromatic Hydrocarbons: A Laboratory and Quantum Chemical Spectroscopic Study of 9-Cyanoanthracene DOI
Vincent J. Esposito, Piero Ferrari, C. Zachary Palmer

et al.

The Journal of Physical Chemistry Letters, Journal Year: 2025, Volume and Issue: unknown, P. 1296 - 1304

Published: Jan. 27, 2025

The CN stretch frequency of neutral, gas-phase 9-cyanoanthracene is 2207 cm–1 (4.531 μm) based on high-resolution infrared absorption experiments coupled with a new hybrid anharmonic quantum chemical methodology. A broad band (full-width at half-maximum 47 cm–1) observed and assigned to multiple transitions, including the fundamental various combination bands that gather intensity from strong coupling bright stretch. computational approach utilizes harmonic force constants double-hybrid rev-DSDPBEP86 functional includes MP2 electron correlation, cubic quartic B3LYP density functional. In combination, this method computes center for 9-cyanoanthracene, direct match experiment. Further, produces difference less than 1 two isomers cyanonaphthalene cyanobenzene. As shown comparison CCSD(T)-F12b computations cyanobenzene, inclusion correlation required properly characterize electronic structure highly withdrawing group polycyclic aromatic hydrocarbons. agreement earlier studies, computation 14 small CN-PAHs narrow (∼20 2207–2229 (4.53–4.48 μm). remainder spectrum below 2000 3000–3120 shows good between experiment theory mean absolute error 16 cm–1, respectively.

Language: Английский

Citations

1
High-Resolution Far- to Near-Infrared Anharmonic Absorption Spectra of Cyano-Substituted Polycyclic Aromatic Hydrocarbons from 300 to 6200 cm−1 DOI
Vincent J. Esposito, Ryan C. Fortenberry, C. Boersma

et al.

ACS Earth and Space Chemistry, Journal Year: 2024, Volume and Issue: 8(9), P. 1890 - 1900

Published: Aug. 14, 2024

Cyano-substituted polycyclic aromatic hydrocarbons (CN-PAHs) may contribute to the emission detected in 7−9 μm (1430−1100 cm−1) and 11−15 (900−670 regions of astronomical IR spectra. Anharmonic quantum chemical computations 14 CN-PAH isomers for 4 small PAHs benzene reveal strong, broad absorption features across entire 300−6200 cm−1 (33−1.6 μm) frequency range. In particular, when an full width at half maximum (fwhm) 15 is applied, composite spectrum greatly overlaps with unsubstituted-PAH range besides 2200−2500 region that arises from strong CN stretch fundamental CN-PAHs addressed a separate publication. At high resolution, however, infrared spectra unique, identifiable 700−950, 1100−1300, 2000−2500, 3400−3600 ranges. The in-plane out-of-plane CH bending vibrational frequencies are shifted comparing their unsubstituted counterparts, making differentiation mixed laboratory experiments possible. overall (2950−3200 first overtone (5950−6200 relatively unaffected by cyano-substitution, changes only covered by, intensity of, bands. Detailed spectroscopic data on normal mode components each state reported herein provide means directly assign future guide direct observations with, e.g., James Webb Space Telescope (JWST).

Language: Английский

Citations

7
Noncovalent Interactions Steer the Formation of Polycyclic Aromatic Hydrocarbons DOI Creative Commons
Daniël B. Rap, Johanna G. M. Schrauwen, Britta Redlich

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(33), P. 23022 - 23033

Published: Aug. 7, 2024

Aromatic molecules play an important role in the chemistry of astronomical environments such as cold interstellar medium (ISM) and (exo)planetary atmospheres. The observed abundances (polycyclic) aromatic hydrocarbons benzonitrile cyanonaphthalenes are, however, highly underestimated by astrochemical models. This demonstrates need for more experimentally verified reaction pathways. low-temperature ion–molecule benzonitrile•+ with acetylene is studied here using a multifaceted approach involving kinetics spectroscopic probing products. A fast radiative association via situ prereactive complex shows importance noncovalent interactions steering pathway during reactions. Product structures subsequent reactions are unambiguously identified infrared action spectroscopy reveal formation nitrogen-containing, linked bicyclic phenylpyridine•+ benzo-N-pentalene+ structures. results, contradicting earlier assumptions on product structure, demonstrate products emphasize possible environments.

Language: Английский

Citations

5
Polycyclic (Anti)aromatic Hydrocarbons: Interstellar Formation and Spectroscopic Characterization of Biphenylene and Benzopentalene DOI
Athena R. Flint, Vincent J. Esposito, Ryan C. Fortenberry

et al.

Physical Chemistry Chemical Physics, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Formation of biphenylene, (C 6 H 4 ) 2 , and its isomer benzopentalene, C 12 8 may act as a consumption route for ortho -benzyne ( o -C in interstellar clouds such TMC-1.

Language: Английский

Citations

0
Infrared Spectroscopic Identification of Mass-Selected Benzonitrile Ions in Neon Matrices: Astrochemical Implications DOI

Wen-Jian Huang,

Sheng‐Lung Chou, Chih‐Hao Chin

et al.

The Journal of Physical Chemistry Letters, Journal Year: 2025, Volume and Issue: unknown, P. 5412 - 5417

Published: May 22, 2025

Benzonitrile (C6H5CN) has emerged as a key astrochemical molecule, yet the vibrational spectra of its ionic forms remain incomplete. In this work, we present first IR absorption mass-selected C6H5CN+ and C6H5CN- isolated in solid neon at 3 K. Distinct features both ions were identified through their differential response to UV photolysis comparison with theoretical predictions frequencies intensities. These results provide valuable spectroscopic benchmarks for identification benzonitrile space highlight effectiveness matrix-isolation techniques resolving structures transient molecular relevant astrochemistry.

Language: Английский

Citations

0
Photoelectron spectroscopy of deprotonated benzonitrile DOI
Eleanor K. Ashworth, James N. Bull

The Journal of Chemical Physics, Journal Year: 2024, Volume and Issue: 161(11)

Published: Sept. 16, 2024

The recent discovery of cyano-substituted aromatic and two-ring polycyclic hydrocarbon molecules in Taurus Molecular Cloud-1 has prompted questions on how the electronic structure excited-state dynamics these are linked with their existence abundance. Here, we report a photodetachment frequency- angle-resolved photoelectron spectroscopy study jet-cooled para-deprotonated benzonitrile (p-[Bzn-H]−). adiabatic detachment energy was determined as 1.70 ± 0.01 eV, good agreement CCSD(T)/aug-cc-pVTZ calculations. spectra across first few electron-volts above threshold dominated by prompt autodetachment processes associated excitation at least five short-lived (tens femtoseconds) temporary anion shaped resonances since cross sections several orders magnitude larger than direct sections. photoexcitation vibronic profile is ≈640 cm−1 ring deformation mode. [Bzn-H]− lacks valence-localized excited state situated below does not exhibit thermionic emission following resonances. Thus, unlikely to be stable many interstellar environments.

Language: Английский

Citations

0
Sequential Reactions of Acetylene with the Benzonitrile Radical Cation: New Insights into Structures and Rate Coefficients of the Covalent Ion Products DOI Creative Commons

Paul W. Sutton,

John Saunier, Ka Un Lao

et al.

The Journal of Physical Chemistry Letters, Journal Year: 2024, Volume and Issue: 15(44), P. 11067 - 11076

Published: Oct. 29, 2024

Benzonitrile radical cations generated in ionizing environments such as solar nebulae and interstellar clouds can react with neutral molecules acetylene to form a variety of nitrogen-containing complex organics. Herein, we present results from mass-selected ion mobility experiments coupled-cluster DFT calculations for the sequential reactions benzonitrile cation (C

Language: Английский

Citations

0