Fig. 2: Bond dissociation curves for Cr2 (X\({}^{1}{\Sigma }_{g}^{+}\)). | Nature Communications

Fig. 2: Bond dissociation curves for Cr2 (X\({}^{1}{\Sigma }_{g}^{+}\)).

From: A cross-entropy corrected hybrid multiconfiguration pair-density functional theory for complex molecular systems

Fig. 2

The bond dissociation curves calculated by CASSCF (darkolivegreen), CASPT2 (olive), tBLYP (darkgoldenrod), tB3LYP (sandybrown), and tB4LYP (lightpink) methods are plotted together with literature curve (black), the curves are also marked with numbers 1, 2, 3, 4, and 5, respectively. The calculated curves are extrapolated from the cc-pVTZ-DK and cc-pVQZ-DK results (CBS/TQ).The active space definition is CAS(12e, 22o) approached by the Density Matrix Renormalization Group (DMRG) method95,96,97,98,99,100,101. The literature curve is an RKR potential energy curve obtained from a fit to experimental vibrational levels60. The dissociation limits (i.e., the calculated binding energies De) are 5.72, 48.52, 16.40, 13.67, 27.18, and 35.97 kcal ⋅ mol−1 for CASSCF, CASPT2, tBLYP, tB3LYP, tB4LYP, and literature. The literature value is from experimentally determined dissociation energy109 carlibrated with ZPE60. Other benchmark literature values include an experimental value of 33.41 kcal ⋅ mol−1 110, an MR-AQCC/CBS value of 31.13 kcal ⋅ mol−1 71, a RASPT2/CBS value of 43.58 kcal ⋅ mol−1 72, and a DMRG-N-electron valence state perturbation theory (DMRG-NEVPT2)/CBS value of 33.44 kcal ⋅ mol−1 111.The total energy of the molecule calculated at r = 20 Å is set to zero. Source data are provided as a Source Data file.

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