First principles calculations

Harvey A N 1999 Applications of first-principles calculations to the correlation of water s second virial coefficient Proc. 13th Int. Conf of the Properties of Water and Steam (Toronto, 12-16 September 1999)... 

Campillo I, Silkin V M, Pitarke J M, Chulkov E V, Rubio A and Echenique P M 2000 First-principles calculations of hot-electron lifetimes in metals Phys. Rev. B 61 13 484-92... 

Anisimov V I, Kuiper P and Nordgren J 1994 First-principles calculation of NIG valence spectra in the impurity-Anderson-model approximation Phys. Rev. B 50 8257-65... 

Anisimov V I, Aryasetiawan F and Liechtenstein A I 1997 First-principles calculations of the electronic structure and spectra of strongly correlated systems The LDA+U method J. Phys. Condens Matters 767... 

E. M. Boczko and C. L. Brooks III. First principles calculation of the folding free energy of a three helix bundle protein. Science, 269 393-396, 1995. 

Mujica A and R J Needs 1993. First-principles Calculations of the Structural Properties, Stability, aind Band Structure of Complex Tetrahedral Phases of Germanium ST12 and BC8. Physical Review B48 17010-17017. 

The standardless approach attempts to apply first principles descriptions of X-ray production to the calculation of interelement relative sensitivities. Several of the key parameters necessary for first principles calculations are poorly known, and the accuracy of the standardless method often suffers when different X-ray families must be used in measuring several elemental constituents in a specimen. 

The number of Auger electrons from a particular element emitted from a volume of material under electron bombardment is proportional to the number of atoms of that element in the volume. However it is seldom possible to make a basic, first principles calculation of the concentration of a particular species from an Auger spectrum. Instead, sensitivity factors are used to account for the unknown parameters in the measurement and applied to the signals of all of the species present which are then summed and each divided by the total to calculate the relative atomic percentages present. 

Recently, first-principle calculations have been reported on model-free TXRF of stratified structures [4.61]. 

The scope of the early papers was to use the SK approach to accurately interpolate the results of first principles calculations of the energy bands and densities of states. An important characteristic of these calculations is that the first, second, and third nearest neighbor interactions are treated as independent parameters, which is advantageous for minimizing the rms deviation from the first principles bands. 

Table 4 Tight-binding vacancy formation energies compared to first-principles calculations and experiment. Energies were computed using a 108 atom supercell. The experimental column shows a range of energies if several experiments have been tabulated. Otherwise the estimated error in the experiment is given.

In table 2 and 3 we present our results for the elastic constants and bulk moduli of the above metals and compare with experiment and first-principles calculations. The elastic constants are calculated by imposing an external strain on the crystal, relaxing any internal parameters (case of hep crystals) to obtain the energy as a function of the strain[8]. These calculations are also an output of onr TB approach, and especially for the hep materials, they would be very costly to be performed from first-principles. For the cubic materials the elastic constants are consistent with the LAPW values and are to within 1.5% of experiment. This is the accepted standard of comparison between first-principles calculations and experiment. An exception is Sr which has a very soft lattice and the accurate determination of elastic constants is problematic. For the hep materials our results are less accurate and specifically in Zr the is seriously underestimated. ... 

W. H. Butler, X.-G. Zhang, D. M. C. Nicholson, T. C. Schulthess, and J. M. MacLaren, First Principles Calculations of Elecuical Conductivity and Giant Magnetoresistance of ColCulCo Spin Valves ,... 

B. Drittler, M. Weinert, R. Zeller and P.H. Dederichs, First-principles calculation of impurity-solution energies in Cu and Ni , Phys. Rev. B39 930 (1989). 

It is interesting to consider the meanings of the terms of ab initio calculations as well as the closely related term first principles calculations . How are these terms currently used by the computational chemistry community Do these terms mean the same thing ... 

In this brief review we illustrated on selected examples how combinatorial computational chemistry based on first principles quantum theory has made tremendous impact on the development of a variety of new materials including catalysts, semiconductors, ceramics, polymers, functional materials, etc. Since the advent of modem computing resources, first principles calculations were employed to clarify the properties of homogeneous catalysts, bulk solids and surfaces, molecular, cluster or periodic models of active sites. Via dynamic mutual interplay between theory and advanced applications both areas profit and develop towards industrial innovations. Thus combinatorial chemistry and modem technology are inevitably intercoimected in the new era opened by entering 21 century and new millennium. 

Takeuchi, N., Chan, C.T. and Ho, K.M. (1989) First-principles calculations of equilibrium ground-state properties of Au and Ag. Physical Review B - Condensed Matter, 40, 1565-1570. 

Yang, X. and Dong, J. (2005) Geometrical and electronic structures of the (5, 3) single-walled gold nanotube from first-principles calculations. Physical Review B -Condensed Matter, 71,233403-1-233403-4. 

Honkala K, Heilman A, Remediakis IN, Logadottir A, Carlsson A, Dahl S, Christensen CH, Nprskov JK. 2005. Ammonia synthesis from first-principles calculations. Science 307 555-558. 

Otani M, Sugino O. 2006. First-principles calculations of charged surfaces and interfaces A plane-wave nonrepeated slab approach. Phys Rev B 73 115407. 

Taylor C, Kelly RG, Neurock M. 2006a. First-principles calculations of the electrochemical reactions of water at an immersed Ni(lll)/H20 interface. J Electrochem Soc 153 (12) E207-E214. 

The first-principles calculation of NIS spectra has several important aspects. First of all, they greatly assist the assignment of NIS spectra. Secondly, the elucidation of the vibrational frequencies and normal mode compositions by means of quantum chemical calculations allows for the interpretation of the observed NIS patterns in terms of geometric and electronic structure and consequently provide a means of critically testing proposals for species of unknown structure. The first-principles calculation also provides an unambiguous way to perform consistent quantitative parameterization of experimental NIS data. Finally, there is another methodological aspect concerning the accuracy of the quantum chemically calculated force fields. Such calculations typically use only the experimental frequencies as reference values. However, apart from the frequencies, NIS probes the shapes of the normal modes for which the iron composition factors are a direct quantitative measure. Thus, by comparison with experimental data, one can assess the quality of the calculated normal mode compositions. 

The Fe(lll)-azide-precursor and the photolysed product were characterized by NIS spectroscopy coupled to detailed DFT calculations [63]. The result of the study provides additional evidence in favor of a low-spin 5=1/2 ground state of the Fe(V)-nitrido complex. Here we show how first-principles calculations assist in quantitative analysis of experimental NIS data for the Fe(lll)-azide complex. 

In summary, the quantitative information on the frequencies, amplitudes, and directions of Fe motion from NIS measurements provides a definitive test of the detailed normal-mode predictions provided by modem quantum chemical calculations. However, first-principles calculations greatly assist in the analysis and interpretation of experimental NIS data, thus revealing a consistent picture of the vibrational dynamics of iron in molecules. 

Klamt A, Eckert F, Diedenhofen M, Beck ME (2003) First Principles Calculations of Aqueous p Values for Organic and Inorganic Acids Using COSMO-RS Reveal an Inconsistency in the Slope of the pKa Scale. J Phys Chem A 107 9380-9386. 

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