Experimental results calculated data, comparison

The results, presented in Table 8, show that in most cases the conformer with the lowest steric energy indeed corresponds to the experimentally most favored one. In addition, several molecules containing the N—C—N moiety were retrieved from the Cambridge Structural Database and calculated with the new parameter set. A comparison between MM2 and X-ray geometries (selected structural parameters only) for two conformers of 1,4,5,8-tetraazadecalin (25, 26) is provided in Table 9 and shows good fit between the experimental and calculated data. 

A comparison of experimental and calculated data for the HETP shows that the equation of Murch [185] and eq. (I52a) give good results. In contrast, the equation of Hands-Whitt [J. Appl. Cheni. (London) 1 (1951) pp. 135 — 140] gives large deviations. 

The model equations were solved using a numerical method witli known parameters (qs and k) of H2S adsorption corrected for hydrodynamics conditions. The parameters for VOC adsorption and L-V model parameters for H2O adsorption where found by fitting the experimental and calculated data. The results of these fittings are present on Fig. 28, where numbers in the plot legends represent the port location. The initial concentration of H2S was 0.15 ppm. Comparison of the H2S breakthrough capacities received finm the Lab test and the Plant... 

The procedure, in analyzing kinetic data by numerical integration, is to postulate a reasonable kinetic scheme, write the differential rate equations, assume estimates for the rate constants, and then to carry out the integration for comparison of the calculated concentration-time curves with the experimental results. The parameters (rate constants) are adjusted to achieve an acceptable fit to the data. Carpen-(ej-48. pp. 76-81 some numerical calculations. Farrow and Edelson and Porter... 

The values of the half-widths of the components of the rotational absorption spectrum of HC1, dissolved in various noble gases, are borrowed from [291]. In order to make this example obvious, a continuous curve is drawn through the calculated points. Comparison between experimental data and calculated results demonstrates, in line with the qualitative agreement, a good numerical coincidence of the observed. /-dependence of the half-widths of the rotational lines with the theoretical one in the case of HC1 dissolved in Kr and Xe. This allows one to estimate the model parameters for these systems dispersion of the potential... 

Another detailed comparative study of B-spline and CMS-Xa calculations that has been presented [57] addresses core and valence-shell PECD in camphor. For this molecule, a substantial amount of relevant experimental PECD data for the core [56] and valence-shell ionization [36, 56, 64, 65] is now available, allowing a full three-way comparison to be performed. Detailed discussion of the interpretation of the experimental results achieved with these calculations is deferred until Section VI.B, but it is helpful here to summarize the conclusions regarding the computational approaches. 

Fig. 5.17 Comparison of the experimental PVDOS determined from NIS measurements on Fe (TPP)(NO) (upper panel) with the PVDOS predicted on the basis of DFT calculations using the B3LYP (center panel) and BP86 (lower panel) functionals. Blue traces represent the PPVDOS Dp (v)for oriented crystals (see Appendix 2, Part III, 3 of CD-ROM), scaled by a factor of 3 for comparison with the total PVDOS Dpe(v)of unoriented polycrystalline powder (red traces). Since the X-ray beam direction k lies 6° from the porphyrin plane, modes involving Fe motion in the plane of the porphyrin are enhanced, and modes with Fe motion primarily normal to the plane are suppressed, in the scaled oriented crystal PVDOS relative to the powder PVDOS. In-plane Fe modes dominate the 200-500 cm range of the data, while Fe motion in modes observed at 74, 128, and 539 cm is predominantly out-of-plane. Crosshatching in the upper panel indicates the area attributable to acoustic modes. In the lower two panels, the Fe-NO bend/stretch modes predicted at 386 and 623 cm , have been artificially shifted to the observed 539 cm frequency to facilitate comparison with the experimental results. Predicted PVDOS are convolved with a 10 cm Gaussian (taken from [101])...

Detailed comparison of calculated and experimental results for the variation of the escape probability with the external field in Lar, LKr, and LXe has been made by Mozumder (1995a, b, 1996) using the data on LET, W value, mobility, and so forth. Experiments are with MeV electrons or beta-emitters having minimum LET in these liquids. The external field generally does not have any preferred direction relative to the track axis. Mozumder (1995a) argues that in such... 

In the past decade, vibronic coupling models have been used extensively and successfully to explain the short-time excited-state dynamics of small to medium-sized molecules [200-202]. In many cases, these models were used in conjunction with the MCTDH method [203-207] and the comparison to experimental data (typically electronic absorption spectra) validated both the MCTDH method and the model potentials, which were obtained by fitting high-level quantum chemistry calculations. In certain cases the ab initio-determined parameters were modified to agree with experimental results (e.g., excitation energies). The MCTDH method assumes the existence of factorizable parameterized PESs and is thus very different from AIMS. However, it does scale more favorably with system size than other numerically exact quantum... 

Using the model parameters of Table II the calculated osmotic coefficient is within 0.15% or better for all solutions investigated. Agreement with the experimental results (17) is within 0.02% or better if ( ci.Br.K = 0.0003 (Table III) instead of zero (Table II). We may conclude from this comparison that the thermodynamic model of Pitzer (Table II) is very realistic. An uncertainty of 0.0003 in i(ic Br K leads to uncertainties of less than 0.4% in log K(x). The largest uncertainty in equilibrium constants may thus be attributed to the original analytical data (j3). 

Table VII shows a comparison with experimental data by Leyko and Piatkiewicz (1 5) at 80 to 110 °C. At high temperatures partial pressures calculated from the BR- and EMNP-methods deviate by up to 20 per cent from the experimental results, whereas van Krevelen s method - extrapolated to 110 °C - yields partial pressures of hydrogen sulfide which are only about 1/4 to 1/5 of the measured values.

System NH -S02 H20 For comparison with calculated data only the experimental results of Johnstone (16) and Boublik et al. (JT 1 ) were used. (Boublik et al. investigated the system NH3-SO2-SO3-H2O only some of their results with very low SO3/SO2 ratios were used for comparison with calculated data). Experimental results by other authors mostly cover very high solute concentrations in the liquid phase (20 molal and more) and are, therefore, not suitable for comparison with the models discussed here. As van Krevelen s method cannot be used for this system, the comparison is limited to the other procedures. Partial pressures of ammonia calculated from the BR-model are generally too large the calculated values exceed the experimental results mostly by a factor larger than 5. The EMNP method generally yields partial pressures which are only about half as large as the measured ones. The calculated partial pressures of SO2 are always too small, for temperatures between 50 and 90 °C the mean deviations a-mount from 20 to 40 per cent for the EMNP-model and from 40 to 70 per cent for the BR-model. 

The potential dependence of C is the basic improvement of the model, in comparison with the Hehnholtz model, which predicts potential-independent capacity. However, a comparison of experimental data and values calculated on the basis of Eq. (4.10) shows that the function C = behaves according to the Gouy-Chapman model in very dilute solutions and at potentials near the minimum (Fig. 4.8). In concentrated solutions, on the other hand, and at p>otentials farther away from the minimum, the theory is in disagreement with experimental results. Once again, a new theory is called for. 

More recently, Fe-DATA (Saunders and Sundman 1996) was used in calculations for a wide variety of duplex stainless steels, and detailed comparisons were made for amoimts of austenite, as a fimction of temperature, and the partition coefficients of various elements in austenite and ferrite. The results of these comparisons are shown in Figs 10.40 and 10.41. In Fig. 10.40, experimental results which have been given as volume fractions have been compared with mole% predictions, which is reasonable as molar voliunes of the two phases are very similar, d for the amount of austenite is less than 4%, of the same order as would be expected for experimental accuracy, and the comparison of elemental partition coefficients is good. C and N levels, which are difficult to measure in practice, are automatically calculated. Where such measurements have been made the comparison is good and the advantage of using a calculation route is further emphasised. 

Ring currents cannot be directly determined by experimental methods. However, comparison of experimental values of magnetic susceptibilities and their exaltations and anisotropies as well as of H-NMR chemical shifts with the respective data calculated from the ring current model points to the adequacy of this model for the interpretation of experimental results. The magnetic susceptibility associated with the ring current / (83BCJ1853), known as the London susceptibility, is given by... 

A more extensive comparison of DFT-predicted adsorption energies with experimental data for CO adsorption on metal surfaces was made using data from 16 different metal surfaces by Abild-Pedersen and Andersson.13 Unlike the earlier comparison by Hammer et al., this study included information on the uncertainties in experimentally measured adsorption energies by comparing multiple experiments for individual surfaces when possible. These uncertainties were estimated to be on the order of 0.1 eV for most surfaces. In situations where multiple experimental results were available, the mean of the reported experimental results was used for comparison with DFT results. For calculations with the PW91 GGA functional, the mean absolute deviation between the DFT and experimental adsorption... 

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