Molecular Force Field and Centrifugal Distortion Constants of Nitrosyl Fluoride

Abstract

The microwave spectrum of nitrosyl fluoride, NOF, has been reinvestigated in the microwave region and extended into the millimeter wave region. Some 80 transitions, consisting of both ``a''‐ and ``b''‐type transitions, have been measured and assigned. These data provide the information required for a centrifugal distortion analysis which yields the following ground‐state rotational parameters (megacycles per second): $$\begin{array}{cccc}\text{A=95\hspace{0.17em}189.77,}& \text{B=11\hspace{0.17em}844.12,}& & \text{C=10\hspace{0.17em}508.31,}\\ {\tau }_{\mathrm{xxxx}}\text{=−0.099630,}& {\tau }_{\mathrm{zzzz}}\text{=−15.586926,}& & {\tau }_{\mathrm{xxzz}}\text{=0.418629,}\\ {\tau }_{\mathrm{xzxz}}\text{=−0.289581,}& H_{\mathrm{JK}}{\text{=2.339×10}}^{\text{−6}}& \mathrm{and}& H_{\mathrm{KJ}}{\text{=−4.946×10}}^{\text{−5}}.\end{array}$$ Combination of infrared data and microwave data yields the following quadratic potential constants millidynes per angstron, $$f_{\text{r1}}{\text{=2.09,\hspace{0.17em}\hspace{0.17em}f}}_{\text{r2}}{\text{=15.08,\hspace{0.17em}\hspace{0.17em}f}}_{{\mathrm{\alpha /d}}^2}{\text{=1.08,\hspace{0.17em}\hspace{0.17em}f}}_{\text{r1r2}}{\text{=1.85,\hspace{0.17em}\hspace{0.17em}f}}_{\text{r1α/d}}\text{=0.17}$$ . Here f_r1 and f_r2 are the N‐F and N‐O bond force constants, respectively, and f_α is the bond‐bending force constant.