Microwave Spectrum of BF

Abstract

Direct rotational transitions have been observed in the ground vibrational state of ¹⁰B¹⁹F and ¹¹B¹⁹F produced in the gas phase by a discharge in flowing BF₃. Measurements on the $\text{J\hspace{0.17em}=\hspace{0.17em}1\hspace{0.17em}←\hspace{0.17em}0}$ transitions yield $B_0{(}^{10}\mathrm{BF}\text{)\hspace{0.17em}=\hspace{0.17em}48 022.63\hspace{0.17em}±\hspace{0.17em}0.08}\mathrm{MHz}{\mathrm{,\; eq}}_0{\mathrm{Q(}}^{10}\mathrm{B}\text{)\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}9.5\hspace{0.17em}±\hspace{0.17em}0.8}\mathrm{MHz}{\mathrm{,\; B}}_0{(}^{11}\mathrm{BF}\text{)\hspace{0.17em}=\hspace{0.17em}45 185.77\hspace{0.17em}±\hspace{0.17em}0.06}\mathrm{MHz}$ , and ${\mathrm{eq}}_0{\mathrm{Q(}}^{11}\mathrm{B}\text{)\hspace{0.17em}=\hspace{0.17em}−\hspace{0.17em}4.5\hspace{0.17em}±\hspace{0.17em}0.4}\mathrm{MHz}$ . New molecular parameters are derived for ¹¹BF including $B_e\text{\hspace{0.17em}=\hspace{0.17em}45 481}\mathrm{MHz}$ , and $r_e\text{\hspace{0.17em}=\hspace{0.17em}1.2625 Å}$ . The electric dipole moment of BF is determined to be 0.5 ± 0.2 D.