Perturbation allowed transitions in the infrared spectrum of ¹⁴ND₃: determination of the <i>K</i>-dependent parameters in the ground state

Accurate values of the <i>K</i>-dependent constants ⁽ <i>ⁱ</i> ⁾ <i>C</i>, ⁽ <i>ⁱ</i> ⁾ <i>D_K </i> and ⁽ <i>ⁱ</i> ⁾ <i>H_K </i> in the ground state of ¹⁴ND₃, with <i>i</i> = <i>s</i>, <i>a</i>, have been determined for the first time thanks to the detections of ‘perturbation allowed’ transitions in the ν₁, ν₂, ν₃, ν₄ and 2ν₄ infrared bands. The rotation–inversion and inversion transitions from the literature, together with 7289 ground state combination differences from the infrared vibration–rotation–inversion transitions have been simultaneously analysed. The adopted rotation–inversion Hamiltonian includes distortion constants up to the eighth power and the Δ<i>k</i> = ±3 and Δ<i>k</i> = ±6 interaction terms. Precise values of the diagonal constants and of the Δ<i>k</i> = ±3 interaction coefficients have been obtained. Accurate values of the ground state term values have been calculated for both <i>s</i> and <i>a</i> levels up to <i>J</i> = 21.本研究首次通过探测ν₁、ν₂、ν₃、ν₄及2ν₄红外带中的“微扰允许”跃迁（perturbation allowed transitions），测定了¹⁴ND₃基态下与K相关的(i)型常数C⁽ⁱ⁾、D_K⁽ⁱ⁾及H_K⁽ⁱ⁾的精确数值，其中i可取s、a两类。本研究同时拟合分析了已发表文献中的转动-反转（rotation–inversion）跃迁与反转跃迁数据，连同7289条来自红外振动-转动-反转跃迁的基态组合差值数据。本次研究所采用的转动-反转哈密顿量（rotation–inversion Hamiltonian）包含至八阶的畸变常数，以及Δk=±3和Δk=±6相互作用项。本研究获得了对角常数以及Δk=±3相互作用系数的精确数值。本研究计算得到了s类与a类能级在转动量子数J≤21时的基态能级项值。