Atomic data

D. D. Cohen and M. Harrigan. Atomic Data and Nuclear Data Tables. 33,... 

Considering that the parameters for the MNDO/d method for all first row elements (which are present in most of the training set of compounds) are identical to MNDO, the improvement by addition of d-functions is quite impressive. It should also be noted that MNDO/d only contains 15 parameters, compared to 18 for PM3, and that some of the 15 parameters are taken from atomic data (analogously to the MNDO/AMl parameterization), and not used in the molecular data fitting as in PM3. 

The j3 parameter is determined by fitting to known atomic data and x is defined in eq. (6.23). 

To obtain the Ey contribution only from calculations over % type functions and from atomic data one needs a more detailed analysis of the equations. Let us consider the following form of Fock operator... 

Raghavan, P. Atomic Data Nucl. Data Tables 42, 189 (1989)... 

Fig. 3. Variation of heats of protonation in the gas phase of bases with N, 0, P, and S donor atoms as hydrogens are replaced by methyl groups as substituents on the donor atoms. Data from Ref. (12).

Fraga, S. Karwovski, J. Saxena, K. M. S. Handbook of Atomic Data Elsevier Amsterdam, 1976. 

A common feature of the various methods that we have developed for the calculation of electronic effects in organic molecules is that they start from fundamental atomic data such as atomic ionization potentials and electron affinities, or atomic polarizability parameters. These atomic data are combined according to specific physical models, to calculate molecular descriptors which take account of the network of bonds. In other words, the constitution of a molecule (the topology) determines the way the procedures (algorithms) walk through the molecule. Again, as previously mentioned, the calculations are performed on the entire molecule. 

We have only just started to explore empirical access to FMO parameters based on these similarities 52). Recently, others have reported empirical equations for calculating IP s and EA s for a variety of Ji-bonded systems 64). This approach used a large number of parameters for the underlying rc-system, heteroatom substitution, and the substituents on the 7t-system. However, we aim at calculating FMO parameters from fundamental atomic data while taking due account of the bond structure of a molecule. 

Astronomical Observatory, were used to carry out the calculations of theoretical equivalent widths of lines, synthetic spectra and a set of plane parallel, line-blanketed, flux constant LTE model atmospheres. The effective temperatures of the stars were determined from photometry, the infrared flux method and corrected, if needed, in order to achieve the LTE excitation balance in the iron abundance results. The gravities were found by forcing Fe I and Fe II to yield the same iron abundances. The microturbulent velocities were determined by forcing Fe I line abundances to be independent of the equivalent width. For more details on the method of analysis and atomic data see Tautvaisiene et al. (2001). 

Basic aim of PMS04 was not to waste valuable sets of measurements acquired during the years by several authors in galactic PNe, whose resulting chemical abundances are however not easy to handle, because of the inhomogeneity of the analyses due to different atomic data and different procedures used by the various authors to interpret the data. We decided to go back to the original measurements and interpret all of them with an unique best assessed procedure. 

Our multi-level carbon model atom is adapted from D. Kiselman (private communication), with improved atomic data and better sampling of some absorption lines. The statistical equilibrium code MULTI (Carlsson 1986), together with ID MARCS stellar model atmospheres for a grid of 168 late-type stars with varying Tefj, log g, [Fe/H] and [C/Fe], were used in all Cl non-LTE spectral line formation calculations, to solve radiative-transfer and rate equations and to find the non-LTE solution for the multi-level atom. We put particular attention in the study of the permitted Cl lines around 9100 A, used by Akerman et al. (2004). 

Chemical abundances are inferred from the EW of the lines. Selected lines and atomic data are from our previous paper [5], from [4] and. Stellar parameters were first inferred from Geneva photometry and Hipparcos parallaxes. Then temperatures, microturbulence velocities, gravities and metallicities were iteratively changed in order to i) obey the excitation equilibrium of the Fe I lines ii) require that Fe I and Fe II abundances agree within 0.1-0.15 dex and iii) require that Fe I lines with different equivalent widths (EW) give the same iron abundance. 

M. J. Seaton, The Opacity Project, Vol. I Selected Research Papers, Atomic Data Tables for Pie to Si Vol II Atomic Data Tables for S to Fe, Photo-ionization Cross-sections Graphs, Inst. Phys. Publ., Bristol, 1996. References to other papers, and papers on atomic data computed in course of the OP are given in the website http //vizier.u-strasbg.fr/topbase/publi.html,... 

Fig. 19 Closure of benzo-3(x + 2)-crown-(x + 2) ethers [20] in 99% Me2SO. Log-log plot of EM against number of ring atoms (data from Illuminati et al., 1981). The line was drawn with the theoretical slope of — 3/2...

Thus, both the mean droplet size and the size distribution may be predicted using these correlations [Eqs. (26), (27), (28), or (29) and Eqs. (30), (31)] for given process parameters and material properties. For a given atomizer design, the standard deviation of droplet size distribution has been found to increase with the melt flow rate, but appears to be less sensitive to the gas flow rated5 Moreover, the variation of the standard deviation is very atomizer- and melt-specific. An empirical correlation which fits with a wide range of atomization data has the following form ... 

It means, for example, that atomic data can only rarely be used as a substitute for molecular integrals since the atom-in-molecule orbitals are not the same as the separate atom orbitals — worse, they are no longer equivalent among themselves. An atomic self-repulsion integral (0j0, 0j0j) is different if 0j is the lone-pair hybrid of NH3 or the bond-pair hybrid as the Gillespie-Nyholm rules suggest. 

Fischer C.F. Average-Energy of Configuration Hartree-Fock Results for the Atoms Helium to KaAon.l/Atomic Data,-1972, -N° 4, -p. 301-399. 

Other atomic data needed, such as electronic charge distributions and screened potentials for partially stripped ions can presumably be based on available tabulations, although existing theoretical treatments have been based on simple and not necessarily accurate scaling relations. 

L. Visscher and K. G. Dyall, Atom. Data Nucl. Data Tables, 1997, 67, 207. 

In summary, the intensity of the analytical line of any of the elements present in the excited volume to the sample is determined by four groups of data. The first ( Sample ) is only dependent on the sample as a whole (density, local thickness), so being common for all elements in the excited volume. The second ( FactovAf) only depends on atomic data, the third is the fraction of the given element (ca) and the fourth is the detection efficiency at the energy of the detected line. (Mass fractions appear in these formulas, as explained in the Appendix.)... 

S. Fraga, J. Karwowski and K.M.A. Saxena Handbook of Atomic Data, Amsterdam Elsevier (1976). 

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