Turbomole is a highly optimized software package for large-scale quantum chemical simulations of molecules, clusters, and periodic solids. It uses Gaussian basis sets and specializes on predictive electronic structure methods with excellent cost to performance characteristics, such as (time-dependent) density functional theory (TDDFT), second-order Møller-Plesset theory, and explicitly correlated coupled cluster (CC) methods. These methods are combined with ultra-efficient and numerically stable algorithms such as integral-direct and Laplace transform methods, resolution-of-the-identity, pair natural orbitals, and fast multipole and low-order scaling techniques. Apart from energies and structures, a variety of optical, electric, and magnetic properties are accessible from analytical energy derivatives for electronic ground and excited states. Recent additions include post-Kohn-Sham calculations within the random-phase approximation, periodic calculations, spin-orbit couplings, explicitly correlated CC singles doubles and perturbative triples methods, CC singles doubles excitation energies, and nonadiabatic molecular dynamics simulations using TDDFT. A dedicated graphical user interface and a user support network are also available.

A new computational approach is presented that allows for an accurate and efficient treatment of the electronic Coulomb term in density functional methods. This multipole accelerated resolution of identity for J (MARI-J) method partitions the Coulomb interactions into the near- and far-field parts. The calculation of the far-field part is performed by a straightforward application of the multipole expansions and the near-field part is evaluated employing expansion of molecular electron densities in atom-centered auxiliary basis sets (RI-J approximation). Compared to full RI-J calculations, up to 6.5-fold CPU time savings are reported for systems with about 1000 atoms without any significant loss of accuracy. Other multipole-based methods are compared with regard to reduction of the CPU times versus the conventional treatment of the Coulomb term. The MARI-J approach compares favorably and offers speedups approaching two orders of magnitude for molecules with about 400 atoms and more than 5000 basis functions. Our new method shows scalings as favorable as N1.5, where N is the number of basis functions, for a variety of systems including dense three-dimensional molecules. Calculations on molecules with up to 1000 atoms and 7000 to 14 000 basis functions, depending on symmetry, can now be easily performed on single processor work stations. Details of the method implementation in the quantum chemical program TURBOMOLE are discussed.

TURBOMOLE is a collaborative, multi-national software development project aiming to provide highly efficient and stable computational tools for quantum chemical simulations of molecules, clusters, periodic systems, and solutions. The TURBOMOLE software suite is optimized for widely available, inexpensive, and resource-efficient hardware such as multi-core workstations and small computer clusters. TURBOMOLE specializes in electronic structure methods with outstanding accuracy–cost ratio, such as density functional theory including local hybrids and the random phase approximation (RPA), GW-Bethe–Salpeter methods, second-order Møller–Plesset theory, and explicitly correlated coupled-cluster methods. TURBOMOLE is based on Gaussian basis sets and has been pivotal for the development of many fast and low-scaling algorithms in the past three decades, such as integral-direct methods, fast multipole methods, the resolution-of-the-identity approximation, imaginary frequency integration, Laplace transform, and pair natural orbital methods. This review focuses on recent additions to TURBOMOLE’s functionality, including excited-state methods, RPA and Green’s function methods, relativistic approaches, high-order molecular properties, solvation effects, and periodic systems. A variety of illustrative applications along with accuracy and timing data are discussed. Moreover, available interfaces to users as well as other software are summarized. TURBOMOLE’s current licensing, distribution, and support model are discussed, and an overview of TURBOMOLE’s development workflow is provided. Challenges such as communication and outreach, software infrastructure, and funding are highlighted.

Thin SiO 2 films were grown on a Ru(0001) single crystal and studied by photoelectron spectroscopy, infrared spectroscopy and scanning probe microscopy. The experimental results in combination with density functional theory calculations provide compelling evidence for the formation of crystalline, double-layer sheet silica weakly bound to a metal substrate. DOI: 10.1103/PhysRevLett.105.146104 PACS numbers: 68.35.Àp, 68.47.Gh, 68.55.Àa Silicon dioxide (SiO 2 ) plays a key role in many modern technologies and applications that range from insulating layers in integrated circuits to supports for metal and oxide clusters in catalysts. For better understanding of structureproperty relationships on silica-based materials, particularly of reduced dimensions, thin silica films grown on metal single crystal substrates are suggested as suitable model systems that allow the facile application of many ''surface science'' techniques. It has recently been shown that crystalline silica films and nanowires can be grown on Mo(112) [1][2][3][4][5]. The ultrathin film consists of a monolayer honeycomblike network of corner-sharing [SiO 4 ] tetrahedra, thus resulting in a SiO 2:5 stoichiometry of the film. The Si atoms in these films can be partly substituted by Al in the course of preparing metal supported aluminosilicate films [6], which is the first step towards experimental modeling of catalytic centers in zeolitelike materials. However, attempts to grow thicker silica films on the Mo substrates resulted in amorphous structures [7][8][9], most likely due to the formation of strong Si-O-Mo bonds at the interface that govern the growth mode [9]. Recently, the preparation of crystalline silica films on other supports such as Pd(100) [10] and Ni(111) [11] has been reported. However, the atomic structure of the films, film surface termination, and the nature of the silica-metal interface were not determined.In this Letter, we report on the preparation and the atomic structure of well-defined silica films on Ru(0001). The experimental results, obtained by photoelectron and vibrational spectroscopies and high-resolution scanning probe microscopy, are complemented by density functional theory calculations which together provide compelling evidence for the formation of a double-layer sheet silicate, with a SiO 2 stoichiometric composition, weakly bound to a metal support. The results open new perspectives for employing a ''surface science'' approach to understand the reactivity of silicate surfaces consisting of hydrophobic Si-O-Si bonds, such as those of microporous all-silica zeolites [12]. Also, these films can be used as model supports for catalytically active metal and oxide clusters [4,13].The experiments were performed in an ultrahigh vacuum chamber equipped with low energy electron diffraction (LEED) and Auger electron spectroscopy, x-ray photoelectron spectroscopy (XPS), infrared reflection absorption spectroscopy (IRAS), and scanning tunneling microscopy (STM). Atomically resolved atomic force microscopy (AFM) and STM image...

Clear as glass: The atomic structure of a metal-supported vitreous thin silica film was resolved using low-temperature scanning tunneling microscopy (STM). Based on the STM image, a model was constructed and the atomic arrangement of the thin silica glass determined (see picture). The total pair correlation function of the structural model shows good agreement with diffraction experiments performed on vitreous silica.

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Dedicated to Süd-Chemie on the occasion of its 150th anniversary Zeolites are crystalline microporous aluminosilicates widely used as molecular sieves and catalysts in industrial chemical processes. Silicon-rich zeolites (Si/Al > 12) such as ZSM-5 (MFI framework) have found particular attention. The catalytically active species, that is, protons, metal cations, and metal-oxo cations, compensate the negative charge of the microporous aluminosilicate frameworks [Si nÀm Al m O 2n ] mÀ made of corner-sharing TO 4 tetrahedra (T = Si, Al À ). A typical feature of many silicon-rich zeolites is a high number of crystallographically distinguishable T sites. Since the cationic species bind to the AlO 4 À tetrahedra, the crystallographic position of aluminum in zeolite frameworks governs the location of the active sites, which in turn affects the catalytic activity and selectivity.Thus, understanding the Al siting in zeolite structures is a priority, but it has remained a challenge. Diffraction methods are of limited use because of the similar scattering properties of Si and Al but also because of the low Al content in the most active zeolite catalysts. Solid-state 29 Si magic-angle spinning (MAS) NMR spectroscopy succeeded early in distinguishing between Si in different crystallographic positions of the MFI framework, [1] but for the quadrupolar 27 Al nucleus, the development of multiple quantum (MQ) NMR spectroscopy experiments [2] opened such possibilities only in the last decade. [3][4][5][6] It is also not clear if there are preferred T sites for Al substitution or whether the T sites are occupied statistically. An X-ray diffraction study found three Cs + sites in extraframework positions of ZSM-5, thus indicating nonrandom Al siting, [7] which is also supported by the effect of the Al concentration on the 27 Al MQ MAS NMR spectra of ZSM-5 [4] and zeolite b.[5] As lattice energy minimizations with reliable force fields, for example, for MFI, [8,9] yielded only small energy differences for Al in different positions, the Al distribution might be kinetically controlled. This assumption implies that different synthesis procedures and different templates and cations could lead to different Al substitution patterns, thus increasing the total number of resolved 27 Al signals in the MQ MAS NMR spectra of a variety of samples. This strategy is followed herein.For a set of 11 differently synthesized ZSM-5 samples, ten distinct resonances have been identified by 27 Al MQ MAS NMR spectroscopy, extending over a shift range of Dd = 13.6 ppm. Quantum-chemical calculations for simulated structures with Al in 24 different T sites yield a shift range of Dd = 14.1 ppm and show that the observed resonances belong to Al in different crystallographic sites. We conclude that the Al siting in ZSM-5 is not random and can be substantially varied by the conditions of zeolite syntheses.A set of Na-ZSM-5 samples (A-K) with Si/Al framework ratios from 14 to 45 was prepared by using different silicon, aluminium, and sodium sources as well as differe...

Ewald summation is used to apply semiempirical long-range dispersion corrections (Grimme, J Comput Chem 2006, 27, 1787; 2004, 25, 1463) to periodic systems in density functional theory. Using the parameters determined before for molecules and the Perdew-Burke-Ernzerhof functional, structure parameters and binding energies for solid methane, graphite, and vanadium pentoxide are determined in close agreement with observed values. For methane, a lattice constant a of 580 pm and a sublimation energy of 11 kJ mol(-1) are calculated. For the layered solids graphite and vanadia, the interlayer distances are 320 pm and 450 pm, respectively, whereas the graphite interlayer energy is -5.5 kJ mol(-1) per carbon atom and layer. Only when adding the semiempirical dispersion corrections, realistic values are obtained for the energies of adsorption of C(4) alkenes in microporous silica (-66 to -73 kJ mol(-1)) and the adsorption and chemisorption (alkoxide formation) of isobutene on acidic sites in the micropores of zeolite ferrierite (-78 to -94 kJ mol(-1)). As expected, errors due to missing self-interaction correction as in the energy for the proton transfer from the acidic site to the alkene forming a carbenium ion are not affected by the dispersion term. The adsorption and reaction energies are compared with the results from Møller-Plesset second-order perturbation theory with basis set extrapolation.