In the emission spectrum of the ${}^{12}{\mathrm{C}}^{17}{\mathrm{O}}^{+}$ isotopologue the Comet-Tail $({\mathrm{A}}^2{\Pi }_{\mathrm{i}}\to {\mathrm{X}}^2{\Sigma }^{+})$ system has been observed and analysed for the first time. 1215 spectral transitions in the 16 950 to 22 000 cm${}^{-1}$ region, belonging to three $\mathrm{A}-\mathrm{X}$ ($1-0,1-1$ and $1-2$) bands, were recorded with the Fourier-transform spectrometer and measured with an accuracy of 0.01 cm${}^{-1}$. As a result of analysis, 15 molecular parameters of the ${\mathrm{A}}^2{\Pi }_{\mathrm{i}}(v=1)$ and ${\mathrm{X}}^2{\Sigma }^{+}(v=0,1,2)$ levels were obtained. The ro-vibronic term values of the ${\mathrm{A}}^2{\Pi }_{\mathrm{i}}(v=1)$ level were also determined. Moreover, a very weak ${\mathrm{A}}^2{\Pi }_{\mathrm{i}}(v=1)\sim {\mathrm{X}}^2{\Sigma }^{+}(v=11)$ perturbation of a complex, spin-orbit, spin-electronic and $\mathbf{\text{L}}-$uncoupling character was identified and worked out. A percentage ${}^2\Pi$ character of the ${\mathrm{A}}^2{\Pi }_{\mathrm{i}}(v=1)$ and ${\mathrm{X}}^2{\Sigma }^{+}(v=11)$ levels was considered in detail.

在发射光谱中${}^{12}{\mathrm{C}}^{17}{\mathrm{○}}^{+}$彗尾同位素$({\mathrm{一个}}^2{\Pi }_{\mathrm{一世}}\to {\mathrm{X}}^2{\Sigma }^{+})$首次对系统进行了观察和分析。16 950 至 22 000 cm 范围内的 1215 次光谱跃迁${}^{-1}$地区，属于三个$\mathrm{一个}-\mathrm{X}$($1-0,1-1$和$1-2$) 波段，用傅里叶变换光谱仪记录，测量精度为 0.01 cm${}^{-1}$. 分析结果显示，15 个分子参数${\mathrm{一个}}^2{\Pi }_{\mathrm{一世}}(v=1)$和${\mathrm{X}}^2{\Sigma }^{+}(v=0,1,2)$获得了水平。的 ro-vibronic 项值${\mathrm{一个}}^2{\Pi }_{\mathrm{一世}}(v=1)$水平也确定了。此外，一个非常弱的${\mathrm{一个}}^2{\Pi }_{\mathrm{一世}}(v=1)～{\mathrm{X}}^2{\Sigma }^{+}(v=11)$复杂的、自旋轨道、自旋电子和$\mathbf{\text{大号}}-$解耦字符被识别并制定出来。一个百分比${}^2\Pi$的性格${\mathrm{一个}}^2{\Pi }_{\mathrm{一世}}(v=1)$和${\mathrm{X}}^2{\Sigma }^{+}(v=11)$水平进行了详细考虑。