Yes, this is a psi4 version issue. You may have acquired or updated psi4 recently, but conda update psi4 only grabs stable releases, the last of which (1.0.54 for Linux conda builds) was July 2016. In development terms, we’re up to ~1.1rc1 from April 2017, but because it’s not a stable release, you have to grab it off the devel subchannel. Follow these directions: