Highly accurate equilibrium structure of the C2h symmetric N1‐to‐O2 hydrogen‐bonded uracil‐dimer. Issue 15 (9th March 2018)

• Record Type: Journal Article
• Authors: Kruse, Holger; Šponer, Jiří
• Is Part Of: International journal of quantum chemistry. Volume 118:Issue 15(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-03-09
• Subjects: composite scheme -- coupled‐cluster -- density functional theory -- geometry optimization -- nucleobases; Quantum chemistry -- Periodicals; 541.28
• DOI: 10.1002/qua.25624
• Languages: English
• ISSNs: 0020-7608

Abstract

Abstract: The highly accurate ab initio equilibrium geometry of the hydrogen‐bonded uracil dimer is derived using a composite geometry extrapolation scheme based on all‐electron, complete basis set extrapolated Møller–Plesset perturbation theory using the jun‐pwCV[T, Q]Z basis sets combined with a valence CCSD(T)/cc‐pVTZ high‐level correction. Geometrical changes on dimerization are discussed and the performance of the several density functional approximations (among others SCAN, ωB97M‐V, DSD‐PBEP86‐D3(BJ), and DSD‐PBEP86‐NL) is evaluated. Orbital‐optimized MP2.5 is discussed as a reduced‐cost alternative to the CCSD(T) gradient in the composite scheme. A new reference interaction energy is calculated with explicitly correlated F12‐CCSD(T). Abstract : Based on a cost‐effective composite gradient approach the structural features of the uracil dimerization are presented with quantum chemical "gold‐standard" accuracy. Highly accurate interaction and deformation energies are obtained. The performance of various lower levels of theories for the structure and energies are evaluated.