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Scanning tunneling microscopy (STM) offers unparalleled sub-molecular resolution for visualizing surface-bound molecular assemblies. We developed a custom 3D-printed liquid cell that enabled stable, long-duration liquid-phase STM imaging of a metallocene dimer assembled on a highly oriented pyrolytic graphite (HOPG) substrate. High-resolution images revealed two distinct molecular packing structures. However, STM alone is difficult to pinpoint the detailed molecular arrangements, resonance Raman spectroscopy (RRS) was used to provide complementary information. Aided with density functional theory (DFT) calculated RRS, a cis conformer of the metallocene dimer was identified as the more probable form in both crystal and surface-bound states. These findings led to assemblies with cyclopentadienyl rings pointing towards the HOPG, and the carbonyl groups towards the water. This work demonstrates the synergistic power of integrating STM, RRS, and DFT in elucidating molecular assembling structures at the solid–liquid interface. 

Free and open source social platform software has dramatically lowered the barrier to entry for anyone to set up and administer their own social network. This new population of social network administrators thus assume data management responsibilities for sociotechnical systems. Administrators have the power to customize this software, including data collection and data retention, potentially leading to radically different privacy policies. To better understand the characteristics — e.g., the variability, prohibitions, and permissions — of privacy policies on these new social networking platforms, we have conducted a case study of Mastodon. We performed a text analysis of 351 privacy policies and a survey of 104 Mastodon administrators. While most administrators used the default policy that ships with the Mastodon software, we observed that approximately ten percent of our sample tailored their privacy policies to their instances and that some administrators conflated codes of conduct with privacy policies. Our findings suggest the existing market-based individualistic frameworks for thinking about privacy policies do not adequately address this emerging community.