I'm not a molecular physicist, so my speculations are bound to be somewhat naive. I'm only hoping to initiate some discussion around the subject, which I thought might be interesting to all. Now that the electronic absorption spectrum of the atomic anti-hydrogen 1s->2s electronic transition has been measured (Nature (2016) doi:10.1038/nature21040 Received 29 November 2016 Accepted 07 December 2016 Published online 19 December 2016 ), I wonder what folks think about the possibility of doing a similar series of experiments on anti-H2. In the above experiment, atomic anti-H was held in a magnetic trap for ~17 sec while the electronic absorption spectrum was collected. The spectrum agreed with that of ordinary H to one part in 1010. If diatomic anti-H could be created, could it also be trapped magnetically,(necessary to hold the antimatter away from ordinary matter of the apparatus), or does that phase of the experiment require the unpaired positron in the anti-atom? Assuming that trapping could be accomplished, and the molecules could be produced, in sufficient quantity to be observed, one would have a 4-body anti-matter system to probe. I would think that the molecule would display positron-positron, antiproton-antiproton, and two types of positron-antiproton interactions, all of which would contribute to the range of molecular orbital transitions that could be observed by means of UV-visible spectroscopy. Also, wouldn't infrared spectroscopy probe the vibrational stretching transitions, the details of which reflect the coulombic repulsion of the nuclei and the stabilization of the molecule through the delocalization of the 2 positrons? A more complex system, to be sure, but therefore one likely to yield more answers.