Advances in theory and algorithms for electronic structure calculations must be incorporated into program packages to enable them to become routinely used by the broader chemical community. This work reviews advances made over the past five years or so that constitute the major improvements contained in a new release of the Q-Chem quantum chemistry package, together with illustrative timings and applications. Specific developments discussed include fast methods for density functional theory calculations, linear scaling evaluation of energies, NMR chemical shifts and electric properties, fast auxiliary basis function methods for correlated energies and gradients, equation-of-motion coupled cluster methods for ground and excited states, geminal wavefunctions, embedding methods and techniques for exploring potential energy surfaces.

Q-Chem 2.0 is a new release of an electronic structure program package, capable of performing first principles calculations on the ground and excited states of molecules using both density functional theory and wave function-based methods. A review of the technical features contained within Q-Chem 2.0 is presented. This article contains brief descriptive discussions of the key physical features of all new algorithms and theoretical models, together with sample calculations that illustrate their performance.

Historic manufacturing enterprises based on vertically optimized companies, practices, market share, and competitiveness are giving way to enterprises that are responsive across an entire value chain to demand dynamic markets and customized product value adds; increased expectations for environmental sustainability, reduced energy usage, and zero incidents; and faster technology and product adoption. Agile innovation and manufacturing combined with radically increased productivity become engines for competitiveness and reinvestment, not simply for decreased cost. A focus on agility, productivity, energy, and environmental sustainability produces opportunities that are far beyond reducing market volatility. Agility directly impacts innovation, time-to-market, and faster, broader exploration of the trade space. These changes, the forces driving them, and new network-based information technologies offering unprecedented insights and analysis are motivating the advent of smart manufacturing and new information technology infrastructure for manufacturing.

The (hyper)polarizabilities of GaN, GaP, and GaAs clusters have been calculated using an ab initio timedependent Hartree-Fock method and an even-tempered Gaussian basis set. The geometries of the clusters used in the study were optimized by ab initio Hartree-Fock calculations using the same basis set. The clusters used in this calculation are of the type Ga m X n (m ) 1, 3, 4 and n ) 1, 3, 4) where X ) N, P, or As. The Ga m X n clusters are in a charge neutral (q ) 0) state for m ) n and in an appropriately charged state for m * n. All of the clusters studied are stable in a nearly tetrahedral geometry. The magnitude of the calculated (hyper)polarizabilities appears to depend on the size of the cluster. The cluster-size dependence of calculated (hyper)polarizabilities is more pronounced for the first hyperpolarizability, β, than for the polarizability, R. The calculated frequency-dependent polarizability, R(ω), exhibits a small but finite dispersion with the frequency of the optical field. The magnitude of the calculated β(-ω σ ;ω 1 ,ω 2 ) corresponding to various second-order effects shows the expected trend of β(-2ω;ω,ω) > β(-ω;0,ω) > β(0;0,0).

With more and more workflow systems adopting cloud as their execution environment, it becomes increasingly challenging on how to efficiently manage various workflows, virtual machines (VMs) and workflow execution on VM instances. To make the system scalable and easy-to-extend, we design a Workflow as a Service (WFaaS) architecture with independent services. A core part of the architecture is how to efficiently respond continuous workflow requests from users and schedule their executions in the cloud. Based on different targets, we propose four heuristic workflow scheduling algorithms for the WFaaS architecture, and analyze the differences and best usages of the algorithms in terms of performance, cost and the price/performance ratio via experimental studies.