Dipolar molecular moment

This transformation suggests that when an aminoacid molecule is introduced from vacuum into the middle of a polar medium, which is the case of the physiological cellular media, a severe change is produced in its properties, its geometry, its energy, the charges which its atoms support, the dipolar molecular moment, etc., set off and conditioned by the presence of the solvent. 

Here the coefficients are given in terms of the dipolar transition moments dv or the corresponding oscillator strengths / , which characterize the creation of the molecular excitations by light / = Y,yfv The states < s.vac> thus defined have been termed generalized doorway (Jortner and Mukamel, 1974), radiant (Voltz, 1974), or spectroscopic (Rhodes and Ziv, 1976) states. 

The choice of solvent is of particular importance. First, it has to be chosen such that the solubility is in a suitable range for the selected type of crystallization experiment (reasonably high solubility for cooling experiments, very low solubility in solvents used for precipitation, etc.). Second, it is important to use solvents with diverse physical properties in order to explore the whole parameter space of possible environments. In addition to molecular solvent-solute interactions, bulk properties of solvents such as viscosity may play a role. Gu et al. [19] examined 96 solvents in terms of 8 relevant solvent properties hydrogen bond acceptor propensity, hydrogen bond donor propensity, polarity/dipolarity, dipole moment, dielectric constant, viscosity, surface tension, and cohesive energy density (calculated from the heat of vaporization). Based on all 8 properties, the 96 solvents were sorted into 15 groups... 

The frequency dependence is taken into accoimt through a mixed time-dependent method which introduces a dipole-moment factor (i.e. a polynomial of first degree in the electronic coordinates ) in a SCF-CI (Self Consistent Field with Configuration Interaction) method (3). The dipolar factor, ensuring the gauge invariance, partly simulates the molecular basis set effects and the influence of the continuum states. A part of these effects is explicitly taken into account in an extrapolation procedure which permits to circumvent the sequels of the truncation of the infinite sum-over- states. 

The relationship between the herbicidal activity of 1,2,5-oxadiazole iV-oxides and some physicochemical properties potentially related to this bioactivity, such as polarity, molecular volume, proton acceptor ability, lipophilicity, and reduction potential, were studied. The semi-empirical MO method AMI was used to calculate theoretical descriptors such as dipolar moment, molecular volume, Mulliken s charge, and the octanol/water partition coefficients (log Po/w) <2005MOL1197>. 

On the other hand, electric dipolar moments of the solute molecules can be obtained with standard methods in ab initio molecular orbital calculations, whereas the induced dipole moments in solution are determined from differences between the values obtained in solution and in the gas phase. 

It should be borne in mind, however, that enzyme proteins, like other proteins, are dipolar ionic structures surrounded by an intense electrostatic field. Horse carboxyhemoglobin, for example, has a dipole moment of 480 Debye units (molecular weight, 67,000). Compared with amino acids, sugars have a rather low dipole moment, due mainly to a considerable measure of mutual cancellation of the constituent link moments resulting from their disposition in space (glycine = 15, a- and... 

He stressed the significance of measurements of molecular dipole moment, the principles of which had been established in 1912 by Debye.52 Ingold predicted that mesomeric systems would display measurable dipole effects. 53 He later said that he realized at this time that the theory of dipolar charge and intermediate form was... 

On the basis of these formulae one can convert measurements of area, which equals the integral in the latter formula, under spectral lines into values of coefficients in a selected radial function for electric dipolar moment for a polar diatomic molecular species. Just such an exercise resulted in the formula for that radial function [129] of HCl in formula 82, combining in this case other data for expectation values (0,7 p(v) 0,7) from measurements of the Stark effect as mentioned above. For applications involving these vibration-rotational matrix elements in emission spectra, the Einstein coefficients for spontaneous emission conform to this relation. 

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