re: What if you could come up with a molecular structure that would cause a greenhouse in reverse?
We already have atomic structures that can do the job, simply detonate few nuclear bombs in the upper atmosphere in such a way that the hot molecules of the atmosphere will evaporate into space, this will reduce the atmospheric pressure and also leave the cool molecules behind. Making a perfect climate for us, but we should check to see if there are any indigenous life forms there before modifying the climate :-)