Microtechnology and Nanoscience, MC2, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
J Phys Condens Matter. 2012 Oct 24;24(42):424212. doi: 10.1088/0953-8984/24/42/424212. Epub 2012 Oct 3.
A recent study of temperature-programmed desorption (TPD) measurements of small linear alkane molecules (n-alkanes, with formula C(N)H(2N+2)) from C(0001) deposited on Pt(111) shows a linear relationship of the desorption energy with increasing n-alkane chain length N. We here present a van der Waals density functional study of the desorption barrier energy of the ten smallest n-alkanes (of carbon chain length N = 1-10) from graphene. We find linear scaling with N, including a non-zero intercept with the energy axis, i.e. an offset at the extrapolation to N = 0. This calculated offset is quantitatively similar to the results of the TPD measurements. From further calculations of the polyethylene polymer we offer a suggestion for the origin of the offset.
最近一项关于在 Pt(111) 上沉积的 C(0001) 上的小线性烷烃分子（n-烷烃，化学式为 C(N)H(2N+2)）的程序升温解吸（TPD）测量的研究表明，解吸能与 n-烷烃链长 N 的增加呈线性关系。我们在这里提出了一个范德华密度泛函研究从石墨烯上脱附的前十种最小的 n-烷烃（碳链长 N = 1-10）的脱附势垒能量。我们发现与 N 的线性比例关系，包括与能量轴的非零截距，即在 N = 0 处的外推存在一个偏移。这种计算出的偏移与 TPD 测量的结果在数量上是相似的。通过进一步计算聚乙烯聚合物，我们提出了偏移的起源的建议。
