By measuring the increments of dielectric capacitance (ΔC) and dissipation (Δtan δ) during physical vapor deposition of a 110 nm film of a molecular glass former, we provide direct evidence of the mobile surface layer that is made responsible for the extraordinary properties of vapor deposited glasses. Depositing at a rate of 0.1 nm s⁻¹ onto a substrate at T_dep = 75 K = 0.82T_g, we observe a 2.5 nm thick surface layer with an average relaxation time of 0.1 s, while the glass growing underneath has a high kinetic stability. The level of Δtan δ continues to decrease for thousands of seconds after terminating the deposition process, indicating a slow aging-like increase in packing density near the surface. At very low deposition temperatures, 32 and 42 K, the surface layer thicknesses and mobilities are reduced, as are the kinetic stabilities.

中文翻译：

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稳定有机玻璃气相沉积过程中的快速表面动力学原位观察

通过测量电介质电容（Δ的增量Ç）和耗散（Δtan  δ分子玻璃形成的110纳米薄膜的物理气相沉积过程中），我们提供了由负责的非凡特性移动表面层的直接证据气相沉积玻璃。在T _dep = 75 K = 0.82 T _g下以0.1 nm s ^-1的速率沉积到基板上，我们观察到2.5 nm厚的表面层的平均弛豫时间为0.1 s，而下面生长的玻璃具有很高的动力学稳定性。Δtan水平 δ在终止沉积过程后，它继续下降了数千秒，这表明表面附近的堆积密度呈缓慢的老化状增长。在非常低的沉积温度（32和42 K）下，表面层的厚度和迁移率以及动力学稳定性都降低了。