The diatomic transition metal selenides, MSe (M = Sc, Y, Ru, Os, Co, Rh, Ir, and Pt), were studied by resonant two-photon ionization spectroscopy near their respective bond dissociation energies. As these molecules exhibit high densities of vibronic states near their dissociation limits, the spectra typically appear quasicontinuously at these energies. Spin–orbit and nonadiabatic couplings among the multitudes of potential curves allow predissociation to occur on a rapid timescale when the molecule is excited to states lying above the ground separated atom limit. This dissociation process occurs so rapidly that the molecules are dissociated before they can be ionized by the absorption of a second photon. This results in an abrupt drop in the ion signal that is assigned as the 0 K bond dissociation energy for the molecule, giving bond dissociation energies of 4.152(3) eV (ScSe), 4.723(3) eV (YSe), 3.482(3) eV (RuSe), 3.613(3) eV (OsSe), 2.971(6) eV (CoSe), 3.039(9) eV (RhSe), 3.591(3) eV (IrSe), and 3.790(31) eV (PtSe). The enthalpies of formation, Δ_fH_0K° (g), for each diatomic metal selenide were calculated using thermochemical cycles, yielding Δ_fH_0K° (g) values of 210.9(4.5) kJ mol⁻¹ (ScSe), 203.5(4.5) kJ mol⁻¹ (YSe), 549.2(4.5) kJ mol⁻¹ (RuSe), 675.9(6.5) kJ mol⁻¹ (OsSe), 373.9(2.6) kJ mol⁻¹ (CoSe), 497.4(2.7) kJ mol⁻¹ (RhSe), 557.4(6.5) kJ mol⁻¹ (IrSe), and 433.7(3.6) kJ mol⁻¹ (PtSe). Utilizing a thermochemical cycle, the ionization energy for ScSe is estimated to be about 7.07 eV. The bonding trends of the transition metal selenides are discussed.

中文翻译：

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双原子过渡金属硒化物的键解离能：ScSe，YSe，RuSe，OsSe，CoSe，RhSe，IrSe和PtSe

通过共振双光子电离光谱法研究了它们各自键解离能附近的双原子过渡金属硒化物MSe（M = Sc，Y，Ru，Os，Co，Rh，Ir和Pt）。由于这些分子在其解离极限附近表现出高密度的振动态，因此光谱通常在这些能量下准连续出现。当分子被激发到高于地面分离的原子极限的状态时，众多势能曲线之间的自旋轨道和非绝热耦合使预离解在快速的时间尺度上发生。这种离解过程发生得如此之快，以至于分子在被第二个光子吸收而被电离之前就被解离了。这导致离子信号突然下降，该信号被分配为该分子的0 K键解离能，给出键解离能为4.152（3）eV（ScSe），4.723（3）eV（YSe），3.482（3）eV（RuSe），3.613（3）eV（OsSe），2.971（6）eV（CoSe）， 3.039（9）eV（RhSe），3.591（3）eV（IrSe）和3.790（31）eV（PtSe）。形成焓Δ_f H _0K °（g），使用热化学循环计算每个双原子金属硒化物，得出的_Δf H _0K °（g）值分别为210.9（4.5）kJ mol ^-1（ScSe），203.5（4.5）kJ mol ^-1（YSe），549.2（4.5）kJ mol ^-1（RuSe），675.9（6.5）kJ mol ^-1（OsSe），373.9（2.6）kJ mol ^-1（CoSe），497.4（2.7）kJ mol ^-1（RhSe ），557.4（6.5）kJ mol ^-1（IrSe）和433.7（3.6）kJ mol ^-1（PtSe）。利用热化学循环，ScSe的电离能估计约为7.07 eV。讨论了过渡金属硒化物的结合趋势。