High resolution infrared spectra of PH${}_3$ were recorded with a Bruker IFS125 HR Fourier transform infrared spectrometer at an optical resolution of 0.0025 cm${}^{-1}$ and analyzed in the region of 600–1700 cm${}^{-1}$ where the ${\nu }_2/{\nu }_4$ bending dyad is located. The number of 2207 and 4564 transitions (in general, 3099 “allowed” and 3672 “forbidden”, which is about 2.5 times higher in comparison with the preceding studies) with $J^{\text{max}}$ = 29, $K^{\text{max}}$ = 28 ($J^{\text{max}}$ = $K^{\text{max}}$ = 24 in the earlier studies) were assigned to these two bands. Ground state parameters were improved on the basis of MW and IR data, known from the literature, and new IR data from the present study. The $A_1/A_2$ splittings for the states with the quantum number $K=13$ were experimentally recorded and theoretically explained for the first time. The weighted fit of 1284 upper energy values obtained from the experimentally recorded transitions was made with a Hamiltonian which takes into account resonance interaction between the $(0100,A_1)$ and $(0001,E)$ vibrational states. As the result, a set of 86 fitted parameters was obtained which reproduces the initial 1284 upper “experimental”ro–vibrational energy values with the $d_{\text{rms}}=9.8\times {10}^{-5}$ cm${}^{-1}$.

PH的高分辨率红外光谱${}_3$ 用布鲁克 IFS125 HR 傅立叶变换红外光谱仪以 0.0025 cm 的光学分辨率记录${}^{-1}$ 并在 600-1700 cm 范围内进行分析${}^{-1}$ 哪里 ${\nu }_2/{\nu }_4$弯曲二元组位于。2207 和 4564 次转换的数量（一般来说，3099 次“允许”和 3672 次“禁止”，与之前的研究相比大约高出 2.5 倍），$J^{\text{最大限度}}$ = 29, ${钾}^{\text{最大限度}}$ = 28 ($J^{\text{最大限度}}$ = ${钾}^{\text{最大限度}}$= 24 在早期的研究中）被分配到这两个频段。在文献中已知的 MW 和 IR 数据以及本研究中的新 IR 数据的基础上改进了基态参数。这${\mathrm{一种}}_1/{\mathrm{一种}}_2$ 具有量子数的状态的分裂 $钾=13$首次进行了实验记录和理论解释。从实验记录的跃迁中获得的 1284 个上能量值的加权拟合是用哈密顿量进行的，它考虑了$(0100,{\mathrm{一种}}_1)$ 和 $(0001,乙)$振动状态。结果，获得了一组 86 个拟合参数，它们再现了初始的 1284 个上“实验”ro-vibrational 能量值$d_{\text{均方根}}=9.8\times {10}^{-5}$ 厘米${}^{-1}$.