Spectroscopic constants for third-row diatomics, calculated with single- and multi-reference methods

First and second vibrational harmonic constants have been calculated for 10, third-row, diatomic molecules. Also included in this dataset are equilibrium bond lengths and energies for each diatomic. These have been calculated by constructing a potential energy curve for each computational method and fitting a polynomial to each curve. The degree and number of points of the polynomial was increased until the quantities converged. Potential energy curves were calculated with traditional coupled-cluster theory (CCSD(T)), quasi-variational coupled-cluster methods (OQVCCD(T), OQVCCDR(T), OQVCCDAR(T)), distinguishable cluster approximation (DCSD), parametrised coupled-cluster (pCCSD), multireference configuration interaction (MRCI, MRCI+Q) and CCSD(T) with relativity and core correlation effects. All calculations were extrapolated between cc-pVQZ and cc-pV5Z basis sets. This dataset includes a .zip archive one text file in the comma-separated value (.csv) format. The columns of the data represent the system, method, equilibrium bond length in angstom (R_e), first vibrational constant in cm^-1 (w_e), second vibrational constant in cm^-1 (w_e x_e) and equilibrium energy in hartree (E_n).