Abstract The major excitation mechanism of palladium ionic lines (Pd II) in glow discharge plasma was investigated when argon, neon, krypton, and argon‑helium mixed gas were employed as the plasma gas. Different types of Pd II lines were intensively excited depending on the kind of the plasma gases. Correspondences in the excitation energy were found for each plasma gas, the excited levels of 8.1–8.6 eV for argon, 13.1–14.4 eV for neon, and more than 15 eV for helium, while no intense Pd II lines were found in krypton. These phenomena are principally attributed to an asymmetric charge transfer collision with the plasma gas ion, as previous studies have pointed out for other metallic elements. However, the excitation scheme of the Pd II lines is somewhat different from the normal scheme for the other metallic elements. In particular, it is a unique feature that the triplet metastable levels, 4d95s 3D3,2,1, rather than the ground state level, 4d10 1S0, of the palladium atom play a critical role in excitations of the Pd II lines. This effect is principally because the total excitation energy follows the energy resonance condition, as well as the spin multiplicity follows the spin conservation rule between the colliding partners.

中文翻译：

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三重态亚稳能级在使用几种等离子体气体的辉光放电等离子体中钯原子电离/激发中的作用

摘要 研究了氩、氖、氪和氩氦混合气体作为等离子体气体时，钯离子线（Pd II）在辉光放电等离子体中的主要激发机制。根据等离子体气体的种类，不同类型的 Pd II 谱线被强烈激发。发现每种等离子体气体的激发能量对应，氩的激发能级为 8.1-8.6 eV，氖的激发能级为 13.1-14.4 eV，氦的激发能级超过 15 eV，而氪中没有发现强烈的 Pd II 谱线。这些现象主要归因于与等离子体气体离子的不对称电荷转移碰撞，正如先前的研究已经指出的其他金属元素。然而，Pd II 线的激发方案与其他金属元素的正常方案略有不同。特别是，钯原子的三重亚稳态能级 4d95s 3D3,2,1 而非基态能级 4d10 1S0 在 Pd II 谱线的激发中起关键作用，这是一个独特的特征。这种效应主要是因为总激发能遵循能量共振条件，并且自旋多重性遵循碰撞伙伴之间的自旋守恒规则。