The adsorption of CO on Mg(001) constitutes a challenge for current density functional approximations because of its weak interaction character. In the present work we show that the M06-2X and M06-HF exchange-correlation functionals are the first ones to provide a simultaneously satisfactory description of adsorbate geometry, vibrational frequency shift, and adsorption energy of CO on MgO(001)....

The binding energy and electronic coupling of perylenediimide (PDI) pi-stacked dimers were calculated using M06-2X/6-31++G** as a function of stacking geometry. Due to shallow minima in the potential energy surface, electronic coupling can vary by over an order of magnitude among energetically accessible geometries. The coupling was then determined for 20 PDI derivatives with various substituti...

BACKGROUND Chemicals generically referred to as flavonoids belong to the group of phenolic compounds and constitute an important group of secondary metabolites due to their applications as well as their biochemical properties. Flavonoids, which share a common benzo- γ-pyrone structure, constitute a kind of compound which are highly ubiquitous in the plant kingdom. FINDINGS The M06 family of d...

The performance of the M06 family of exchange-correlation potentials for describing the electronic structure and the Heisenberg magnetic coupling constant (J) is investigated using a set of representative open-shell systems involving two unpaired electrons. The set of molecular systems studied has well defined structures, and their magnetic coupling values are known experimentally. As a general...

The Gibbs energy of reaction of oxidative addition of ammonia to an iridium complex in diethyl ether was calculated by seven density functional methods, in particular B3LYP, PBE, CAMB3LYP, M05, M06, M06-L, and oB97X. The calculated free energies, based on geometry optimization and frequency calculations in both the gas phase and solution, were compared with the experimental result, 1.3 kcal mol...

In this paper we assess the accuracy of the B3LYP, X3LYP, and newly developed M06-L, M06-2X, and M06 functionals to predict the binding energies of neutral and charged water clusters including (H2O)n, n = 2-8, 20), H3O(+)(H2O)n, n = 1-6, and OH(-)(H2O)n, n = 1-6. We also compare the predicted energies of two ion hydration and neutralization reactions on the basis of the calculated binding energ...

As gold clusters increase in size, the preferred structure changes from planar to three-dimensional and, for anionic clusters, Au(n)-, the two-dimensional(2D)-->three-dimensional (3D) transition is found experimentally to occur between n=11 and n=12. Most density functionals predict that planar structures are preferred up to higher n than is observed experimentally, an exception being the local...

Accurate description of hydrogen-bonding energies between water molecules and van der Waals interactions between guest molecules and host water cages is crucial for study of methane hydrates (MHs). Using high-level ab initio MP2 and CCSD(T) results as the reference, we carefully assessed the performance of a variety of exchange-correlation functionals and various basis sets in describing the no...

We present two new hybrid meta exchangecorrelation functionals, called M06 and M06-2X. The M06 functional is parametrized including both transition metals and nonmetals, whereas the M06-2X functional is a highnonlocality functional with double the amount of nonlocal exchange (2X), and it is parametrized only for nonmetals.The functionals, alongwith the previously publishedM06-L local functional...

The performance of the time-dependent density functional theory (TDDFT) approach has been evaluated for the electronic spectrum of the UO(2)(2+), NUO(+) and NUN molecules. Different exchange-correlation functionals (LDA, PBE, BLYP, B3LYP, PBE0, M06, M06-L, M06-2X, CAM-B3LYP) and the SAOP model potential have been investigated, as has the relative importance of the adiabatic local density approx...