Theoretical spectroscopic characterization of the ArBeO complex

Using the recently developed explicitly correlated coupled cluster method in connection with the aug-cc-pVTZ basis set, we generated the three-dimensional potential energy surface (3D-PES) of the ground state of the Ar-BeO complex. This PES covers the regions of the global and local minima, the saddle point, and the dissociation of the complex. The PES is also used for the calculation of the rovibrational spectrum up to the dissociation limit. The high density of levels which is observed favors the mixing of the states and hence the occurrence of anharmonic resonances. The wavefunctions of the high rovibrational levels exhibit large amplitude motions in addition to strong anharmonic resonances. Our theoretical spectrum should be helpful in identifying the van der Waals modes of this complex in laboratory.