Knowledge Bank

Spectra of the PF $A\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Pi 0,1,2(v\prime =3-11)-X3\Sigma -(0)$ bands were recorded using laser excitation spectroscopy. The PF molecules in the ground electronic state $X3\Sigma -$ were produced by passing a $He-PF3$ mixture through a microwave discharge in a flow reactor at room temperature. The obtained spectroscopic constants are consistent with the earlier results of Douglas and $Frackoviaka$ for $v\prime =0-2$. The strong dependence of the lambda doubling in the $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Pi 0$ state on the vibrational quantum number and irregular spacing of the vibrational energies indicate interactions with the $b\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}\Sigma +$ and another $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}\Pi$ state. The dipole function of the A-X transition was calculated from the radiative lifetimes and dispersed fluorescence spectra.