The high-resolution microwave rotational spectrum was measured for 2-aminopyridine in the 4.5–13.2 GHz range using a pulsed beam Fourier transform microwave spectrometer. The measured transitions for the parent isotopologue in the 0+ vibrational state of the amino group inversion vibration were used to determine accurate rotational constants and quadrupole coupling constants for the two 14N atoms in the molecule. The molecular parameters determined for the 2-aminopyridine in 0+ vibrational state have the following values: A = 5780.374(1) MHz, B = 2733.5017(3) MHz, C = 1857.6768(3) MHz, 1.5χaa (14N1) = 3.5789(45) MHz, 0.25(χbb – χcc) (14N1) = 1.5033(24)MHz, 1.5χaa (14N2) = -0.0958(70) MHz, and 0.25(χbb – χcc) (14N2) = −1.1615(21) MHz. The measured quadrupole coupling constants are in excellent agreement with those calculated using different computational methods and basis sets. It is noted that the calculation using the MP2 functional with cc-pvDz basis set closely reproduces the experimental values for quadrupole coupling constants for the two 14N atoms.
- Hyperfine structure
- Microwave spectroscopy
- Quadrupole coupling
- Rotational constants
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Physical and Theoretical Chemistry