RT Journal Article
T1 Ab Initio Characterization of C2 H4 N2 Isomers: Structures, electronic energies, spectroscopic parameters and formation pathways
A1 Godwin, Oko Emmanuel
A1 Inostroza, Natalia
A1 Mardones, Diego
A1 Bizzocchi, Luca
A1 Mendoza, Edgar
A1 Senent, María Luisa
A1 Carvajal Zaera, Miguel
AB This work presents a comprehensive theoretical investigation of key isomers of C2H4N2 using state-of-the-art quantum chemical methods. The objective is to characterize their molecular structures, spectroscopic constants, and electronic energies and to elucidate plausible formation and destruction pathways, providing data critical for astrochemical and atmospheric detection. High-accuracy ab initio methods were employed, notably CCSD(T)-F12/cc-pVTZ-F12 for optimized geometries. Additional calculations were performed at the CCSD(T)/aug-cc-pVTZ, CCSD(T)/cc-pVTZ, MP2/aug-cc-pVTZ, and CIS levels. Intrinsic reaction coordinate calculations were performed at the B3LYP/6-31G(d,p) level to explore reaction pathways. The Zero-Point Energy (ZPE)-corrections were determined for all the isomers considered. Six low-energy C2H4N2 isomers were identified, all within 1 eV of the global minimum. Among them, methylcyanamide (MCA) exhibits the lowest relative energy (∼0.2 eV) and a significant electric dipole moment of 5.00 D, making it a strong candidate for detection in gas-phase environments. The rotational constants for MCA, computed at the level of CCSD(T)-F12/cc-pVTZ-F12, are Ae = 34 932.44 MHz, Be = 4995.31 MHz, and Ce = 4520.30 MHz. The V3 torsional barrier was found to be 631.19 cm−1. Centrifugal distortion constants were computed up to sextic order for all isomers. Formation pathways for MCA—such as CH3N + HCN → CH3NHCN—and related isomers were characterized. The combination of large dipole moments and distinct rotational signatures supports the detectability of MCA and related C2H4N2 isomers via radioastronomy, IR, and MW spectroscopy. Isomerization and reaction pathways involving radical-neutral and neutral-neutral processes were found to be key to their formation in gas-phase environments. These results offer a robust foundation for future observational and modeling efforts.
PB American Institute of Physics
SN 0021-9606
SN 1089-7690 (electrónico)
YR 2026
FD 2026
LK https://hdl.handle.net/10272/28010
UL https://hdl.handle.net/10272/28010
LA eng
NO Godwin, O. E., Inostroza, N., Mardones, D., Bizzocchi, L., Mendoza, E., Senent, M. L., & Carvajal, M. (2026). Ab initio characterization of C2H4N2 isomers: Structures, electronic energies, spectroscopic parameters, and formation pathways. The Journal of Chemical Physics, 164(4). https://doi.org/10.1063/5.0294525
DS Repositorio Institucional de la Universidad de Huelva
RD 30 may 2026