who used a scanning tunneling microscope to directly visualize a local time-averaged density of molecules on a surface. This method is of special importance as it provides an opportunity to probe local properties of 2D gases; for instance it enables to directly visualize a pair correlation function of a 2D molecular gas in a real space.
The ability to directly visualize the local density of molecules on a surface using a scanning tunneling microscope provides valuable information about their spatial arrangement and interactions in a two-dimensional gas environment. This technique allows researchers to study the pair correlation function, which is crucial for understanding the behavior of these gases.