A simple gas can form 'fake' molecules where particles clump together even though nothing is actually holding them there.
March 24, 2026
Original Paper
Quantum corrections and multioccupancy in a semi-classical gas
arXiv · 2603.20703
The Takeaway
Normally, molecules require chemical bonds—a physical 'glue'—to hold atoms together. This research shows that gas particles can form multi-particle structures simply by accidentally moving at the exact same speed, creating temporary groups that act like molecules despite having nothing actually holding them together.
From the abstract
The quantum corrections to the behavior of a semi-classical gas can be expressed as a power series of the ratio $eta$ between the cube of De Broglie's thermal wavelength and the specific volume. The connection between $eta$ and the multioccupancy of quantum states is the aim of the present work. By means of a chemical/physical approach it is possible to associate $eta$ to the concrete realization of multioccupancy in momentum space, through the formation of what we call "pseudo-molecules", i.e.