K$_2$ 的 $A^1Σ^+_u$ 和 $b^3Π_u$ 态在整个束缚能量范围内的傅里叶变换光谱与全局退微扰处理
Fourier-transform spectroscopy and global deperturbation treatment of the $A^1Σ^+_u$ and $b^3Π_u$ states of K$_2$ in the entire bound energy range
AI总结：
本研究通过傅里叶变换光谱和全局退微扰处理，精确分析了K$_2$分子$A$和$b$态的耦合能级，获得了解离能和长程系数。
摘要：
记录了 K$_2$ 分子激光诱导荧光（LIF）$A^1Σ^+_u\sim b^3Π_u \rightarrow X^1Σ^+_g$ 的转动分辨傅里叶变换光谱并进行了分析，得到了 $^{39}$K$_2$ 同位素体的自旋-轨道（SO）耦合 $A \sim b$ 复合体的 4053 个能级值，精度约为 0.01 cm$^{-1}$。将这些数据与先前发表文献中的 1739 个能级值合并，覆盖了从较低 $b^3Π_u$ 态底部到原子渐近线 $4s\\;^2{\rm S}_{1/2}$ + $4p\\;^2{\rm P}_{1/2}$ 附近的能量范围 [9955, 17436] cm$^{-1}$，转动量子数 $J\in[0,149]$。实验数据通过直接的 6×6 耦合通道（CC）退微扰处理进行分析，该处理明确考虑了六个态（$A^1Σ^+_u$(0)、$b^3Π_u$(0,1,2)、$c^3Σ_u$(1) 和 $B^1Π_u$(1)）之间的 SO 和电子-转动相互作用。全局退微扰模型的初始参数通过应用多参考组态相互作用和耦合簇方法的 {\it ab initio} 电子结构计算进行估计。对 $A$ 和 $b$ 态解析定义的原子间势函数、三重态 $b$ 态的 SO 分裂以及 $A\sim b$ SO 耦合函数进行了精化，以拟合 $^{39}$K$_2$ 同位素体的 5792 个能级值，其余参数固定在其 {\it ab initio} 值上。得到的 CC 模型的质量不变参数再现了 $^{39}$K$_2$ 的 $A \sim b$ 复合体的整体振转能级能量，精度在实验误差范围内。该退微扰分析提供了精化的解离能 $T_{dis}$=17474.569(5) cm$^{-1}$ 和与相对论原子极限 $4s$+$4p$ 相关的长程系数 $C_3^Σ$ = 5.501(4) $\times10^5$cm$^{-1}$ A$^3$。
英文摘要：
Rotationally-resolved Fourier-transform spectra of laser-induced fluorescence (LIF) $A^1Σ^+_u\sim b^3Π_u \rightarrow X^1Σ^+_g$ of K$_2$ molecules were recorded and analyzed yielding 4053 term values of spin-orbit (SO) coupled $A \sim b$ complex of $^{39}$K$_2$ isotopologue with ca 0.01 cm$^{-1}$ accuracy. Their compilation with 1739 term values from previously published sources allowed to cover the energy range [9955, 17436] cm$^{-1}$ from the bottom of the lower-lying $b^3Π_u$ state up to the vicinity of the atomic asymptote $4s\;^2{\rm S}_{1/2}$ + $4p\;^2{\rm P}_{1/2}$, with rotational quantum number $J\in[0,149]$. The experimental data were processed by a direct 6$\times$6 coupled-channel (CC) deperturbation treatment, which accounted explicitly for both SO and electronic-rotational interactions between six states: $A^1Σ^+_u$($0$), $b^3Π_u$(0,1,2), $c^3Σ_u$(1), and $B^1Π_u$(1). The initial parameters of the global deperturbation model have been estimated in the framework of {\it ab initio} electronic structure calculations applying multi-referenced configuration-interaction and coupled-clusters methods. The interatomic potentials analytically defined for $A$ and $b$ states, as well as SO-splitting of the triplet $b$ state and $A\sim b$ SO-coupling functions have been refined to fit 5792 term values of the $^{39}$K$_2$ isotopologue, whereas the rest parameters were fixed on their {\it ab initio} values. The resulting mass-invariant parameters of the CC model reproduced the overall rovibronic term energies of the $A \sim b$ complex of $^{39}$K$_2$ with the accuracy, which is well within the experimental errors. This deperturbation analysis provided the refined dissociation energy $T_{dis}$=17474.569(5) cm$^{-1}$ and the long-range coefficient $C_3^Σ$ = 5.501(4) $\times10^5$cm$^{-1}$ A$^3$ relevant to the non-relativistic atomic limit $4s$+$4p$.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
