High-resolution laser spectroscopy on the <i>A</i>³Π ← <i>X</i>³Σ⁻ transition of NH

Abstract

In a molecular beam, laser-induced fluorescence experiment, rotational spectra of the A 3 Π, ν = 0 ← X 3 Σ − , ν = 0 transition of the NH free radical were measured at 336 nm with high resolution. From more than 300 completely resolved hyperfine lines, the hyperfine structure of the A 3 Π excited state and the X 3 Σ − ground state could be analyzed. For the first time, the hyperfine coupling constants a N.H , b N.H , c N.H , d N . H , eQq 1 , and eQq 2 in the A 3 Π state were determined. Also, the nuclear quadrupole coupling constant eQq 1 in the X 3 Σ − ground state was obtained.