Correlation, effects dipole moments

The simulation of the liquid has given a vaporization energy underestimated by 7%, while pressure appears to be overcorrected with respect to MCY at 305 K (P =-1180 + 470atm). Experimental specific heat is well reproduced, as pair correlation functions, apart from the usual shift to larger distance of the first peak of the 0-0 g(r). The effective dipole moment is 2.8 D and diffusion coefficient (r> = 2.5 0.110" cmVs) compares well with the experimental data at 25 C, = 2.4-10" cm /s). Experimental is reproduced... 

Figure 9.6. Comparison of the "experimental" effective dipole moment p.(298K) at room temperature, calculated from observed dielectric constants, refractive indices and molar volumes, with l(298K) calculated from the values predicted for the same properties by using the new correlations developed in this book, for 40 polymers. 

Using the extrapolated ciystal packing ratios for one-dimensional arrays of MNA, the global packing ratios were calculated within the multiplicative scheme and then used to evaluate the effective dipole moment, polarizability and first hypetpolarizability of the MNA dimer in the crystal. Finally, the correspon g macroscopic quantities were evaluated. Although electron correlation effects have been indirectly accounted for, our estimates still underestimate the available x experimental values. On the other hand, the... 

Here ct = d z— )yl2> is effective dipole moment, y is Lorenz factor, which takes into account the difference between average and local field acting on the impurity ion, fc is correlation radius of the host lattice [27]. 

Here Id sa /yl, 8 determines the correlation energy, X is extrapolation length of the film in paraelectric phase, E is a mean field in a bulk relaxor, d is the effective dipole moment corrected by Lorenz field, e is dielectric permittivity of a host film. 

Here, f, Fx and are local field factors, a is a molecular parameter including the dipole moment, second order and third order hyperpolarizabilities. Under condition F = Fx = the formula does not agree with the experiment for 8CB. Indeed, it follows that rji should increase at the transition from the nematic to smectic A phase according to the increase in (F2) However, in the experiment, Fn markedly decreases. The similar temperature behavior was earlier observed for dielectric permittivity of 8CB. In the latter case the decrease in is due to the antiparallel correlation of molecular dipoles in the smectic A phase, which results in a decrease in the effective dipole moment /x Thus, the decrease... 

Tni is the nematic to isotropic transition temperature). According to experiment [14], the additivity law holds both for weak and strong polar mixtures of liquid crystal compounds. However, in the latter case the specific intermolecular interaction between mixture components must be taken into account. Indeed, if the structural units of the liquid crystal are not only molecules, but also dimers (Fig. 2.5), then the effective dipole moment of the molecule in (2.12) must be replaced to this one of dimer /Lia Ma 9 where is the dipole correlation factor [14]. For the compounds, shown in Fig. 2.5 with R = C4H9 the correlation factor g 0.5. 

After the application of this correction, the effect of basis-set incompleteness was considered. Comparing the CCSD(T) dipole moments of the three basis sets in Table 15.11, we note that the differences are rather small. Indeed, in no case was it deemed necessary to adjust the correlation-corrected dipole moment, although the uncertainties were adjusted. The uncertainties in Table 15.10 therefore reflect both basis-s errors and errors in the correlation treatment. 

In effect, i is replaced by the vibrationally averaged electronic dipole moment iave,iv for each initial vibrational state that can be involved, and the time correlation function thus becomes ... 

Azulene does have an appreciable dipole moment (0.8 The essentially single-bond nature of the shared bond indicates, however, that the conjugation is principally around the periphery of the molecule. Several MO calculations have been applied to azulene. At the MNDO and STO-3G levels, structures with considerable bond alternation are found as the minimum-energy structures. Calculations which include electron correlation effects give a delocalized n system as the minimum-energy structure. ... 

Of the five sets which were correlated with eq. (2), four gave significant correlations. Values of Pr are in the range 50 to 54, which indicates approximately equal contributions of the localized and delocalized effects. Thus, dipole moments of substituted acetylenes could be correlated successfully with the Up constants. 

No correlation was observed between the dipole moment of the additive and its effect on the stereoselectivity. Thus, CH3CN, whose dielectric constant, 35, is about the same as that of CH3OH, has no effect on the trans/cis ratio of the product. On the other hand, octanol, whose dielectric constant is less than 10, is about as effective as CH3OH in affecting the stereoselectivity. 

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