Only very few molar polarizabilities are known with high accuracy; and when so, they are in general only known at a given wavelength. There is therefore a need to assess the molar polarizability with high accuracy of various gases, at different wavelengths. The molar polarizability of a gas is a measure of the susceptibility of a molecule to have its charge distribution affected by light. It is also the entity that relates the index of refraction to the (molar) density of a gas in Lorentz-Lorenz equation. Hence, for high precision measurements of the density of a gas, it is important to know the molar polarizability of the gas to high accuracy. In this work a GAMOR system has been used to determine the wavelength-dependent molar polarizability of Ar at 1550 nm. However, a high accuracy assessment of the molar polarizability of a gas requires that the gas density is known with high accuracy. Since this is not trivial to assess, the molar polarizability of argon has been assessed in terms of that of nitrogen, which is assumed to be known with high accuracy. Hence, to minimise measurement errors, the measurement cavity was alternately filled with nitrogen and argon and the ratio between the signals provided by the GAMOR system represents the ratio of the molar polarizabilities of the two gases. It was found that the molar polarizability of argon was 0.94393(5) times that of nitrogen. Since the latter one has been assessed to 4.34828(3) x 10^-6 m^/mol, the molar polarizability of argon could be assessed to 4.10446(5) x 10^-6 m^3/mol.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:umu-148557 |
| Date | January 2018 |
| Creators | Zachmann, Nils |
| Publisher | Umeå universitet, Institutionen för fysik |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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