Concrete fracture behavior is predicted by one of multi-scaling methods, called the virtual internal bond (VIB) model. The VIB model describes the microscopic interactions between the cement pastes and aggregates using the concept of homogenization. The microscopic behavior is connected to macroscopic behavior by the Cauchy-Born rule, which results in the strain energy function. From the macros...

We present an accurate interatomic potential for graphene, constructed using the Gaussian Approximation Potential (GAP) machine learning methodology. This GAP model obtains a faithful representation of a density functional theory (DFT) potential energy surface, facilitating highly accurate (approaching the accuracy of ab initio methods) molecular dynamics simulations. This is achieved at a comp...

The authors report extensive high-level ab initio studies of the first excited (Ã (2)A(')) state of HO(2). A global potential energy surface (PES) was developed by spline-fitting 17 000 ab initio points at the internal contracted multireference configuration interaction (icMRCI) level with the AVQZ basis set. To ascertain the spectroscopic accuracy of the PES, the near-equilibrium region of the...

Similar to the importance of XRD in experiments, ab initio calculations, as a powerful tool, have been applied to predict the new potential materials and investigate the intrinsic properties of materials in theory. As a typical solid-solution material, the large degree of uncertainty of high-entropy alloys (HEAs) results in the difficulty of ab initio calculations application to HEAs. The prese...

The first high resolution spectroscopic data for jet cooled H2DO+ are reported, specifically via infrared laser direct absorption in the OH stretching region with a slit supersonic jet discharge source. Transitions sampling upper (0-) and lower (0+) tunneling states for both symmetric (nu1+ <-- 0+, nu1- <-- 0-, and nu1- <-- 0+) and antisymmetric (nu3+ <-- 0+ and nu3- <-- 0-) OH stretching bands...

We have calculated the melting temperature of tungsten by two ab initio approaches. The first approach can be divided into two steps. In the first step, we simulate a large coexisting solid and liquid system by the classical embedded-atom method potential and obtain an approximate melting temperature. In the second step, we compute the accurate melting temperature by performing the ab initio fr...

An ab initio Wannier-function-based approach to electronic groundstate calculations for crystalline solids is outlined. In the framework of the linear combination of atomic orbitals method the infinite character of the solid is rigorously taken into account. The Hartree-Fock groundstate energy, cohesive energy, lattice constant and bulk modulus are calculated in a fully ab initio manner as it i...