Vibrational excitation potentially enhances the energy efficiency of plasma dissociation of stable molecules and may open new routes for energy storage and process electrification. Electron, vibrational and rotational temperatures were measured by in situ Thomson and Raman scattering in order to assess the opportunities and limitations of the essential vibration-translation non-equilibria in N₂, CO₂ and CH₄ plasma. Electron temperatures of 1.1–2.8 eV were measured in N₂ and CH₄. These are used to confirm predominant energy transfer to vibrations after an initial phase of significant electronic excitation and ionization. The vibrational temperatures initially exceed rotational temperatures by almost 8000 K in N₂, by 900 K in CO₂, and by 300 K in CH₄. Equilibration is observed at the 0.1 ms timescale. Based on the vibrational temperatures, the vibrational loss rates for different channels are estimated. In N₂, vibrational quenching via N atoms is identified as the dominant equilibration mechanism. Atomic nitrogen population reaches a mole fraction of more than 1%, as inferred from the afterglow emission decay, and explains a gas heating rate of 25 K μs⁻¹. CH₄ equilibration at 1200 K is predominantly caused by vibrational-translational relaxation in CH₄–CH₄ collisions. As for CO2, vibrational-translational relaxation via parent molecules is responsible for a large fraction of the observed heating, whereas product-mediated VT relaxation is not significantly contributing. It is suggested that electronic excitation, followed by dissociation or quenching contributes to the remaining heat generation. In conclusion, the time window to profit from vibrational excitation under the present conditions is limiting practical application.

振动激发潜在地提高了稳定分子的等离子体离解的能量效率，并可能为能量存储和过程电气化开辟新的途径。电子，振动和旋转温度通过原位汤姆森和拉曼散射测量，以评估N ₂，CO ₂和CH ₄等离子体中基本振动平移非平衡的机会和局限性。在N ₂和CH ₄中测得的电子温度为1.1–2.8 eV。这些用于确认在明显的电子激发和电离的初始阶段之后，能量主要传递给振动。振动温度最初在N _2中超过旋转温度近8000 K，在CO _2中超过900 K，在CH _4中超过300K 。在0.1 ms的时间刻度上观察到平衡。基于振动温度，估计不同通道的振动损失率。在N _2中，通过N原子进行的振动猝灭被认为是主要的平衡机制。原子氮人口达到的超过1％的摩尔分数，如从余辉发射衰减推断，并解释了25 K A气体加热速率μ小号^-1。CH ₄在1200 K时的平衡主要是由CH ₄ –CH ₄碰撞中的振动和平移松弛引起的。至于二氧化碳，经由母体分子的振动-翻译松弛是所观察到的大部分热量的原因，而产物介导的VT松弛没有显着贡献。建议电子激发，然后解离或淬灭有助于产生剩余的热量。总之，在当前条件下从振动激励中获利的时间窗口限制了实际应用。