A new local density functional for main-group thermochemistry, transition metal bonding, thermochemical kinetics, and noncovalent interactions

TLDR

Local density functionals offer computational advantages, making the new M06‑L functional especially useful for moderate‑ to large‑size chemistry simulations and long time‑scale studies. The authors introduce M06‑L, a new local density functional aimed at improving main‑group and transition‑metal thermochemistry, thermochemical kinetics, and noncovalent interactions. M06‑L is parametrized to capture the exchange‑correlation energy dependence on local spin density, spin‑density gradient, and spin kinetic energy density while satisfying the uniform‑electron‑gas limit for both main‑group and transition‑metal chemistry. Compared with 14 other functionals, M06‑L delivers the best overall performance for main‑group thermochemistry, thermochemical kinetics, organometallic, inorganometallic, biological, and noncovalent interactions, and it also accurately predicts geometries and vibrational frequencies.

Abstract

We present a new local density functional, called M06-L, for main-group and transition element thermochemistry, thermochemical kinetics, and noncovalent interactions. The functional is designed to capture the main dependence of the exchange-correlation energy on local spin density, spin density gradient, and spin kinetic energy density, and it is parametrized to satisfy the uniform-electron-gas limit and to have good performance for both main-group chemistry and transition metal chemistry. The M06-L functional and 14 other functionals have been comparatively assessed against 22 energetic databases. Among the tested functionals, which include the popular B3LYP, BLYP, and BP86 functionals as well as our previous M05 functional, the M06-L functional gives the best overall performance for a combination of main-group thermochemistry, thermochemical kinetics, and organometallic, inorganometallic, biological, and noncovalent interactions. It also does very well for predicting geometries and vibrational frequencies. Because of the computational advantages of local functionals, the present functional should be very useful for many applications in chemistry, especially for simulations on moderate-sized and large systems and when long time scales must be addressed.