Microwave spectroscopy of planar and quasi-planar organic molecules: Indole and 1,2,3,4-tetrahydroquinoline

Nesvadba, Radim; Vávra, Karel; Luková, K.; Kania, P.; Koucký, Jan; Urban, Štěpán

doi:10.1016/j.jqsrt.2020.107033

Cited by 3 publications

(2 citation statements)

References 28 publications

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“…On PANH molecules, PGOPHER is extensively utilised in astrophysical studies. 24,44,45 Lorentzian line shape functions have been used to simulate the spectra with an FWHM value of 100 KHz as the line widths are typically 100-300 KHz in experiments. 27 Since the presence of 14 N(I = 1) nuclei can split the rotational lines in the centimetre (cm) wavelength region for hyperfine structures, the 14 N-nuclear quadrupole hyperfine structures are also simulated.…”

Section: Methodsmentioning

confidence: 99%

Theoretical microwave spectra of interstellar nitrogen-containing PAHs

Vats¹,

Srivastav²,

Pandey³

et al. 2023

Phys. Chem. Chem. Phys.

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Section: Methodsmentioning

confidence: 99%

Theoretical microwave spectra of interstellar nitrogen-containing PAHs

Vats¹,

Srivastav²,

Pandey³

et al. 2023

Phys. Chem. Chem. Phys.

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“…At the second-order vibrational perturbation theory (VPT2) level, rotational-vibrational coupling, anharmonic and quartic centrifugal-distortion corrections were considered to obtain all the simulated spectra. PGOPHER is frequently used in astrophysical context on PANH molecules (Nesvadba et al 2020;Chitarra et al 2021). In PGOPHER, the Watson's A-reduced effective rotational Hamiltonian up to the sixth order terms were coupled with the nuclear quadrupole terms to obtain the transition frequencies and assigned rotational and hyperfine quantum numbers J KaKc and F. Because of the existence of 14 N(I = 1) nuclei, the lines in the cm region show resolved hyperfine splitting (McNaughton et al 2018).…”

Section: Sample and Theoretical Methodsmentioning

confidence: 99%

Rotational spectra of interstellar N- and CN-PAHs: pyrene and coronene

Vats

Pathak

2022

Monthly Notices of the Royal Astronomical Society

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The detection of benzonitrile (C6H5CN), 1- and 2-cyano-naphthalene (C10H7CN) in the cold, dark molecular cloud TMC-1 at centimetre (cm) wavelengths has opened up prospects for the detection of other N- and CN-containing polycyclic aromatic hydrocarbons (PAHs). In this light, the pure rotational spectra of N-pyrene (C15H9N), CN-pyrene (C15H9CN), N-coronene (C23H11N) and CN-coronene (C23H11CN) are reported here for the first time. The B3LYP/6-311+G(d,p) level of theory, in the Density Functional Theory (DFT) calculations, achieves the best performance for calculating the spectroscopic parameters and simulating the rotational spectra. The large permanent dipole moment of CN-PAHs makes them the most suitable PAH species for detection in the interstellar medium. Additionally, pyrene’s smaller partition function makes CN-pyrene a prime candidate to be discovered in cold, dark molecular clouds such as the TMC-1. The present work sets a benchmark for theoretical rotational spectra of N- and CN-containing PAHs and may act as a guide for laboratory experiments and observational searches.

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Toward Accurate Characterization of the Puzzling NSO and SNO Moieties

Barone,

Uribe,

Srivastav

et al. 2024

ACS Earth Space Chem.

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The structural and spectroscopic properties in the gas phase of prototypical compounds containing the NSO and SNO moieties have been analyzed by a general computational strategy based on recent Pisa composite schemes (PCS). In a first step, an accurate semiexperimental (SE) equilibrium structure has been derived for cis-HNSO and employed, together with the already available SE equilibrium structures of cis-and trans-HSNO, to validate the geometrical parameters delivered by different quantum chemical methods. The results confirm the accuracy of the proposed composite schemes, provided that the complementary auxiliary basis set correction is included for the Hartree−Fock component. However, perturbative inclusion of quadruple excitations is mandatory for obtaining a correct S−N bond length in the case of HSNO. In this way, it is possible to obtain accurate geometrical parameters and ground state rotational constants, employing in the latter case vibrational corrections obtained by methods rooted in density functional theory (DFT) in the framework of second-order vibrational perturbation theory. The results delivered by a much cheaper model based on DFT geometry optimizations and one-parameter bond corrections, while slightly less accurate, represent a remarkable improvement with respect to current methods of comparable cost. The nearly identical correction induced by quadruple excitations on the S−N bond length of HSNO and CH 3 SNO paves the way toward the study of larger compounds of biochemical interest containing the NSO or SNO moieties.

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Microwave spectroscopy of planar and quasi-planar organic molecules: Indole and 1,2,3,4-tetrahydroquinoline

Cited by 3 publications

References 28 publications

Theoretical microwave spectra of interstellar nitrogen-containing PAHs

Theoretical microwave spectra of interstellar nitrogen-containing PAHs

Rotational spectra of interstellar N- and CN-PAHs: pyrene and coronene

Toward Accurate Characterization of the Puzzling NSO and SNO Moieties

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