Knowledge Bank

Structures of the PF family ($n$=1--5) were characterized with high level RCCSD(T) coupled cluster theory calculations using triple and quadruple zeta quality correlation consistent basis sets. In addition to accounting for the well-known ground states of PF through PF$5$, insight from the recoupled pair bonding model also led to locating a previously unknown $3B1$ state of PF$3$, which lies about 90 kcal/mol above PF$3$($1A1$) but is still bound with respect to PF$2$($2B1$)+F($2P$) by about 40 kcal/mol. We also revisited the less-studied $C3v$ local minimum on the PF$4$ doublet surface and characterized the transition state for interconversion to the $C2v$ global minimum. The energetics suggest that both PF$3$($3B1$) and $C3v$ PF$4$($2A1$) are potentially observable in the laboratory. The trends in the bond dissociation energies and relative energy differences of the PF family are very consistent with predictions from the recoupled pair bonding model.