INDEX of water

All proteins, independent on their aminoadd con odtion, aher the refi active index of water by a dmilar amount per unit mass, and thus there is a linear correlation between the surfiice concentration of protein and the resonance angle shift. 1000 resonance units (RU) corre ond to a 0.1° shift in the SPR angle and this is equivalent to a surfiice concentration change of about 1 ng mmr. ... 

Notice, that with these extremely good resolutions in case of surface sensing contamination of the sensitive layer with solid particles has to be avoided completely, e.g. by an appropriate filtering of the sample solutions. Notice also that the temperature coefficient of the refractive index of water is about 10-4 per °C. So if applying the surface sensing mode using watery solutions indeed a perfect balance of both branches and low temperature gradients have to be aimed at. 

Several anthropogenic constituents which are present in the atmosphere are potentially useful as an index of water age. Two radioactive gases from nuclear weapons and from power reactors, 3H and 85Kr, have been discussed already. Several other radionuclides of man-made origin are present in the atmosphere and in... 

It is well known that the low refractive index of water (n = 1.33) causes problems for the construction of optical waveguides that guide light efficiently through... 

If we take m = 1.333 as the average refractive index of water over the visible spectrum, we obtain... 

Salinity measurements are most often used in oceanography to determine seawater density. The conventional measure used by oceanographers for determining salinity is conductivity. This is feasible because the salt content of seawater is well defined, as is the temperature-related compressibility. As an alternative, the refractive index of water is a good descriptor of density when temperature is known or can be measured. Refractive index provides a high-precision method for determining the density of pure water. As various salts are added, the refractive index is a less exact predictor of density, although relative measurements can still be useful. 

Eisenberg, H. 1965. Equation for the refractive index of water.. 1. Chem. Phys. 43 3887-3892. 

Physical Properties of Liquid Water Refractive Index of Water... 

For absolute take the value asoiute = 4 x ICC20 cm3 previously derived for ew take the square of the refractive index of water, ew = 1.3332 = 1.78. 

Thormahlen, I., Straub J. and Grigul. U., Refractive Index of Water and Its Dependence on Wavelength, Temperature, and Density. J. Phys. Chem. Ref. Data (1985) 14 933-945. 

Table 5 shows the experimental specific refractivities, K X) = n(l) l]/ p, and the average polarizability as calculated from equation (1) at a number of frequencies for liquid and vapour phases. The values of the specific refractivity of the vapour have been obtained from the Cauchy dispersion formula of Zeiss and Meath.39 In this paper the authors assess the results of a number of experimental determinations of the refractive index of water vapour and its variation with frequency. Even after some normalization of the data to harmonize the absolute values from different determinations there is a one or two percent spread of results at any one wavelength. Extrapolation of the renormalized data for five independent sets of data leads to zero frequency values of K(7.) within the range (2.985-3.013) x 10-4 m3 kg 1, giving, via equation (1), LL — 9.63 0.10 au. Extrapolation of the earlier refractive index data of Cuthbertson and Cuthbertson40 by Russell and Spackman41 from 8 values of frequency between 0.068 and 0.095 au, leads to a zero frequency value, of y.i, 1,(0) = 9.83 au. While the considerable variation between the raw experimental data reported in different determinations is cause for some uncertainty, it appears that the most convincing analysis to date is that of... 

The refractive index n of a medium measures the extent of interaction between electromagnetic radiation and the medium through which it passes. It is defined by n = civ. For example, the refractive index of water at room temperature is 1.33, which means that radiation passes through water at a rate of c/1.33 or 2.26 X 10 °cm s . In other words, light travels 1.33 times slower in water than it does in a vacuum. The velocity and wavelength of radiation become proportionally smaller as the radiation passes from a vacuum or from air to a denser medium, while the frequency remains constant. 

The van der Waals forces are significantly affected by the medium of the gap between tip and sample. For example, when the medium is water rather than a vacuum, the forces will be greatly reduced because the dielectric constant and refractive index of water are closer to those of a solid than of a vacuum. 

Given that the refraetive index of water at 25°C is 1.3325 and its molar volume 18.07 em, estimate the moleeular polarizability of the water moleeule. Then estimate the same quantity at 50°C where the value of n is 1.3291, and the molar volume 18.234 em. ... 

Figure 12. Solid curve the refractive index of water showing a simple, monotonic dispersion curve. Dotted curve the contribution of the 189 nm band of iV-methylacetamide at a 1 M concentration added on to the water curve using equation 19. The point to be made is that there is no way to match the background curve of a good solvent to the anomalous dispersion of a chromophoric system under study. Such matching is commonly attempted to remove light scattering problems which depend on the difference in refractive index of the particle, n, with that of the solvent, n, i.e., (tip—nf). The dashed curve adds the second dispersion term in equation 25. Also included is the calculated refractive index of particulate poly-L-glutamic acid (PGA) (see section 4(cKii))-...

The refractive index of water at 20 C is 1.3330. Measure it just before you measure your unknown liquid. Suppose it is 1.3336 or 0.0006 higher than normal. You should then subtract 0.0006 from the unknown to reduce it to 20 °C. 

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