Abstract This work describes 2-mercaptobenzothiazole (MBT) and 2-mercaptobenzimidazole (MBI) adsorption on Cu(111) by a systematic DFT study. Whatever the surface coverage of the adsorbed molecule, the adsorption is favored when the exocyclic sulfur atom is unprotonated (i.e. thione and thiolate forms). At low molecular density, the molecules adsorb forming a Cu-S(exo) and a Cu-N bond, and the adsorption energies of both molecules are similar, around 1.2 eV. To investigate a coverage corresponding to the density of self-assembled films, two strategies were applied: on the one hand, the best epitaxial relationship between the molecular layer and the Cu(111) surface was searched. A reasonable accommodation was found for a molecular density of 3.9 molecule/nm² in the honeycomb (3 × 3) Cu(111) superstructure, in which the molecules are adsorbed with the C2v axis tilted, forming two Cu-S bonds for MBT and one Cu-S and one Cu-N bond for MBI. On the other hand, the best structure for atomic S on Cu(111), the (√7 x √7) R19° superstructure, with a molecular coverage of 5 molecule/nm2, was considered. We find that the honeycomb MBT and MBI layer is the most stable arrangement, showing that in this case, the molecular organization prevails over the head-group/surface interaction. The MBI molecule adsorbs more strongly than the MBT molecule, due to better lateral interactions in the organic layer.

中文翻译：

---

2-巯基苯并噻唑和2-巯基苯并咪唑作为铜缓蚀剂的DFT研究

摘要 这项工作通过系统的 DFT 研究描述了 2-巯基苯并噻唑 (MBT) 和 2-巯基苯并咪唑 (MBI) 在 Cu(111) 上的吸附。无论吸附分子的表面覆盖率如何，当环外硫原子未质子化（即硫酮和硫醇盐形式）时，吸附是有利的。在低分子密度下，分子吸附形成 Cu-S(exo) 和 Cu-N 键，两种分子的吸附能相似，约为 1.2 eV。为了研究与自组装膜密度相对应的覆盖率，应用了两种策略：一方面，搜索分子层和 Cu(111) 表面之间的最佳外延关系。发现蜂窝 (3 × 3) Cu(111) 超结构中分子密度为 3.9 分子/nm² 的合理调节，其中分子在 C2v 轴倾斜的情况下被吸附，形成两个用于 MBT 的 Cu-S 键和一个用于 MBI 的 Cu-S 和一个 Cu-N 键。另一方面，考虑了 Cu(111) 上原子 S 的最佳结构，即 (√7 x √7) R19° 超结构，分子覆盖率为 5 分子/nm2。我们发现蜂窝状 MBT 和 MBI 层是最稳定的排列，表明在这种情况下，分子组织优于头基/表面相互作用。由于有机层中更好的横向相互作用，MBI 分子比 MBT 分子吸附更强。我们发现蜂窝状 MBT 和 MBI 层是最稳定的排列，表明在这种情况下，分子组织优于头基/表面相互作用。由于有机层中更好的横向相互作用，MBI 分子比 MBT 分子吸附更强。我们发现蜂窝状 MBT 和 MBI 层是最稳定的排列，表明在这种情况下，分子组织优于头基/表面相互作用。由于有机层中更好的横向相互作用，MBI 分子比 MBT 分子吸附更强。