I am interested in predicting the infrared spectra of bulk phase molecules, it seems that AIMD (ab initio molecular dynamics) is the current best approach. I have found a tutorial on using CP2K to do exactly this, and I have seen a recent publication for computing condensed phase infrared spectra. I'm not entirely sure how different condensed phase and bulkd phase spectra would be (I guess this could be a bonus question; Whats the difference between bulk phase and condensed phase infrared spectra).

The mentioned above CP2K method seems to be very time consuming, I was wondering if there are other methods for doing these calculations?