SU802853A1 - Method of refractometry of optically transparent liquids and gases - Google Patents

Description

(54) METHOD OF REFRACTOMETRY OF OPTICAL TRANSPARENT LIQUIDS AND GASES

one

The invention relates to electro-optical instrumentation and can be used in various fields of physical and chemical research.

A known method of refractometric analysis is based on the phenomenon of two-beam interferometry and provides a measure of the refractive index of gaseous and condensed media by comparing it with the refractive index of a reference substance.

There is also a known method for the refractometry of optically transparent liquids and gases by separating two collimated beams, passing one of them through the medium under study, combining the beams into studies of the interference pattern |. The absolute value of the refractive index of the test substance is determined by the formula

Ml

P,

(P

uh

where H is the absolute value of the refractive index of the test substance;

P . - the absolute value of the Reflexion Aj-atom of the Reference substance;

N is the number of interference shift bands; I - probing wavelength

radiation, cm; B is the length of the cuvette, see Here, the absolute value of the refractive index of the reference substance is determined in advance with the required accuracy for its state parameters during measurement.

Claims (1)

The disadvantage of this method is that in order to measure the refractive index of the test substance in a wide range of values, it is necessary to carry out measurements at different geometric lengths of the compared samples, which leads to a significant methodological measurement conditions. The purpose of the invention is to simplify the measurement of absolute (refractive index values. The goal is achieved by changing the optical path length of the beam in the medium under study, while calculating the number of bands of the variable terferential pattern, measuring the change in the geometric length by the beam in the medium under study. , and the absolute value of the detour index is determined from the formula where P is the absolute value of the refractive index we investigate (middle I is the wavelength of the outgoing radiation; N is the number of interference los Ij - change of the geometric path length of the beam in the test medium dividing beam 1 into two beams 3 in 4, cuvettes 5 with mirrors 6 and 7 under study, counter 8 and device 9 for moving the cuvette. The device operates as follows. The collimated light beam by the semitransparent mirror 2 is divided into two beams 3 and 4, while beam 3, reaching the deaf mirror 7, returns and, mirror 2, comes down with beam 4. The last one, passing through this mirror, falls into the cuvette 5 with the test material and reflected from the mirror 6, placed in the test substance, passes through the substance for the second time and enters the mirror 2 again, reflected from, is reduced to beam 3. Then, interfering, the rays fall on the counter of 8 interference fringes. Using device 9, mirror 6 moves along the cuvette, occupying different positions and changing the optical path length of the beam in the next substance. Since this changes the path difference between the 3 6 34 34 and 4 beams, then a running interference pattern appears on the 8 strip counter, and the counter captures each strip. The proposed method provides a direct measurement of the absolute value of the refractive index with high accuracy eliminates the qpaBHeHHe studied and reference; first substances using different high-precision high-precision optical cells, simplifies the method of information processing and the refractometric analysis of gaseous and condensed optically transparent substances in a wide range of their parameters state, which allows to reduce the time and cost of information received. Claims The method of refractometry of optically transparent liquids and gases by separating two collimated beams, passing one of them through the medium under study, mixing the beams and studying the interference pattern, characterized in that, in order to simplify the measurement of the absolute value of the index of refraction, the optical path length is changed in the examined medium, the number of bands of the variable interference pattern is counted, the altered geometrical length of the path of the beam in the studied medium is measured, and The absolute value of the index of laziness is determined by the formula 1G where n is the absolute value of the index. refraction of the test medium; I is the probing radiation wavelength; N is the number of interference fringes; CI is the change in the geometric length of the path of the beam in the medium under study. Sources of information taken into account in examination 1, US Patent No. 368О963, cl. Q O1 N 21/46, published. 1972. 2, Ioffe B.V. Refractometric methods in chemistry. M., Gostekhizdat, 1960, p. 223 (prototype).