Density Functional Exploration of C4H3N Isomers.

Area of Science:

• Astrochemistry
• Computational Chemistry
• Quantum Chemistry

Background:

• Molecules with C4H3N stoichiometry are of significant interest in astrophysics.
• Methylcyanoacetylene (CH3C3N) and allenyl cyanide (H2CCCHN) are known interstellar C4H3N species.
• Several other C4H3N isomers have been studied in laboratory settings.

Purpose of the Study:

• To computationally investigate a wide range of C4H3N isomers.
• To predict key molecular parameters for these isomers.
• To support the identification of newly synthesized or observed C4H3N molecules.

Main Methods:

• Density functional theory (DFT) calculations using the B3LYP/aug-cc-pVTZ level of theory.
• Calculation of molecular energetics, geometries, and spectroscopic properties.
• Determination of electronic properties such as excitation energies and spin-state splittings.

Main Results:

• Comprehensive data on energetics, geometries, rotational constants, dipole moments, polarizabilities, and vibrational spectra (IR and Raman) for various C4H3N isomers.
• Predicted singlet-triplet splittings and vertical electronic excitation energies for selected species.
• Quantum chemical predictions provide a basis for experimental identification.

Conclusions:

• The study provides essential theoretical data for characterizing C4H3N molecules.
• These computational predictions are crucial for identifying less stable C4H3N isomers in spectroscopic experiments.
• The findings contribute to the understanding of molecular complexity in interstellar environments.