Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm, Germany.
Phys Chem Chem Phys. 2010 Jan 28;12(4):818-22. doi: 10.1039/b920481d. Epub 2009 Nov 25.
Thermal desorption (TD) of oligopyridine from HOPG shifts from approximately 700 to approximately 500 K when going from (sub-)mono- to multilayers. Stabilization of low coverages results from a continuous shift of the frequency factor nu, from 10(15) s(-1) for submonolayers to 10(24) s(-1) for multilayers, whereas the desorption barrier is virtually constant. Applying transition state theory (TST), we can explain this by a change from rotationally/translationally mobile, flat-lying molecules (submonolayers) to immobile, upright molecules (multilayers). At room temperature, (time resolved) scanning tunneling microscopy (STM) gives evidence for the existence and the stability of the mobile phase.
寡吡啶从 HOPG 上的热解吸（TD）当从（亚）单层到多层时，从大约 700 K 转移到大约 500 K。低覆盖率的稳定化是由于频率因子 nu 的连续移动，从亚单层的 10(15) s(-1) 到多层的 10(24) s(-1)，而解吸势垒几乎不变。应用过渡态理论（TST），我们可以通过从旋转/平移移动的、平躺的分子（亚单层）到不可移动的、直立的分子（多层）来解释这一点。在室温下，（时间分辨）扫描隧道显微镜（STM）证明了移动相的存在和稳定性。
