Charge transfer excitations with range separated functionals using improved virtual orbitals

We present an implementation of range separated functionals utilizing the Slater-function on grids in real space in the projector augmented waves method. The screened Poisson equation is solved to evaluate the necessary screened exchange integrals on Cartesian grids. The implementation is verified against existing literature and applied to the description of charge transfer excitations. We find very slow convergence for calculations within linear response time-dependent density functional theory and unoccupied orbitals of the canonical Fock operator. Convergence can be severely improved by using Huzinaga's virtual orbitals instead. This combination furthermore enables an accurate determination of long-range charge transfer excitations by means of ground-state calculations.Comment: 11 pages + 9 pages supporting information, 5 figures in main text, 3 figures in supporting informatio

A note on near-surface VACM measurements made from three different kinds of surface moorings

During a multi-institutional air-sea interaction experiment (GATE) in the central Atlantic North Equatorial Countercurrent in September 1974, vector-averaging current meter (VACM) measurements were made within the 30-m thick mixed layer from three different types of surface moorings. The moorings consisted of a single-point taut-line flexible mooring (E3), a spar-buoy (El), and a 2-legged mooring (Fl). Although the kinetic energy density spectral estimates of the E3, El, and Fl records in the low frequency range were equivalent with 95% confidence, the mean progressive vector diagrams differed by 6 % in length and 4 in direction. At frequencies above 1 cph the variances of the 7.2 m Fl current vectors were about 1.5 times larger than the 7.6 m E3 data and the spectral levels of the 20 m El and 21.4 m E3 record were equivalent, suggesting that VACM current vectors recorded near the surface beneath a surface-following buoy do not contain detectable amounts of aliased high-frequency mooring motion

Internet Surveys by Direct Mailing: An Innovative Way of Collecting Data

This article describes a new method of collecting data by direct mailing via the Internet. Feasibility and capacities were evaluated through a worldwide opinion poll on global future risks of mankind and potential solutions. Within 1 day, a structured questionnaire was sent to 8,859 randomly selected e-mail addresses. One thousand seven hundred and thirteen were remailed properly completed, 90 within 4 days. Most respondents were residents of North America (64) and Europe (21 ), male (87), and 30 years old on average. Environmental destruction (52) was mentioned as the primary problem, followed by violence (45) and unemployment (45). Education (71 ) was the most frequently proposed solution to future problems. It is obvious that Internet surveys at this time are not repre sentative of the total population. However, they open new dimensions in the interrogation of experts and opinion leaders, especially considering their efficiency and potential for automation