Using ab initio alloy theory, we investigate the equilibrium bulk properties and elastic mechanics of the single bcc solid-solution AlxHf1−xNbTaTiZr (x = 0–0.7, 1.0) high entropy alloys. Ab initio predicted equilibrium volume is consistent with the available experiment. We make a detailed investigation of the alloying effect of Al and Hf on the equilibrium volume, elastic constants and polycrys...

Complex formation of Zr, Hf, and Rf in HF and HCl solutions has been studied both experimentally and theoretically [1,2]. Trends in Kd (distribution coefficient) values evidencing the strengths of formed complexes were shown to be influenced by such factors as pH of solution and acid concentration. Presently, experiments are under way to investigate complex formation of these elements in H2SO4 ...

The reaction between vibrationally excited H2 and F2 had previously been suggested to be a critical chain-branching step in the combustion of mixtures containing H2 and F2. In the present study, the vibrational state specific dynamics and kinetics for the reaction H2 + F2 → H + HF + F were investigated by quasiclassical trajectory (QCT) and quantum mechanical (QM) reactive scattering calculatio...

Straightforward applications of standard quantum chemical methods to biomolecules and nano materials are essentially impossible because of the undesired computational time required for the calculations, scaling at least cubically with the system size N. Up to now, many types of accelerating techniques for the quantum chemical calculations, which reduce the complexity to O(N), have been develope...

Hartree-Fock ~HF! and density functional theory calculations indicate that a ~4,0! carbon nanotube ~CNT! of sub-0.4-nm diameter is stable and its heat of formation is close to that of the stable C36 (D6h). Semiempirical molecular-orbital calculation shows that such narrow tubular structure is more stable than the corresponding opened fragment in the innermost zone of a large CNT. Simulated TEM ...

Stationary points for four geometrically different states of methylene: bent and linear triplet methylene, bent and linear singlet methylene were investigated using the highly reliable post-HF CCSD(T) method. Extrapolations to the CCSD(T) basis set (CBS) limit from Dunning triple to quintuple correlation consistent polarized basis sets were performed for total energies, for the equilibrium CH d...

The stability of cyclopentadiene is determined using quantum Monte Carlo in both the VMC and DMC variants, HF, CCSD(T), LDA, and the BPW91, B3PW91, BLYP, B3LYP generalized gradient approximation (GGA) density functional theory methods. A comparison with available experimental data shows that the GGAs perform signi®cantly better than LDA and HF for structure optimization. The cyclopentadiene ato...

In [19], we introduced absolute gradings on the three-manifold invariants developed in [18] and [21]. Coupled with the surgery long exact sequences, we obtain a number of threeand four-dimensional applications of this absolute grading including strengthenings of the “complexity bounds” derived in [21], restrictions on knots whose surgeries give rise to lens spaces, and calculations of HF for a ...

The monitoring and regulation of one's own physiological reactions and cardioregulatory abnormalities are central to the aetiology and maintenance of social anxiety disorder (SAD). We therefore explored the neural correspondences of these heart rate alterations. 21 patients with SAD and 21 matched healthy controls (HCs) underwent 3T-fMRI scanning. Simultaneously, high-frequency heart rate varia...