Measurementand calculation of Raman spectroscopy of NaNO3,KNO3 AND NaNO2 molten salts

Molten mixture of NaNO3,KNO3 and NaNO2 are widely used as heat transfer and heat storage medium in modern industry. The structure of the molten salts is closely related to their thermophysical properties. The structure change of NaNO3,KNO3 and NaNO2 molten salts under different temperatures is studied by Raman spectroscopy method combined with quantum chemical calculation. The results show that the half width of Raman characteristic peaks of these three substances increases with the increase of temperature. The relationship equation between the Raman frequency shift and the N-O bond length of v1 characteristic peak of N-O ion clusters in the three kinds of melts is obtained. It is also found that v1 characteristic peak of NO-3 in melting NaNO3 and KNO3 shows red shift,and NO-2 in melting NaNO2 shows blue shift. With temperature increasing,N-O bond length of N-O complex in three melting salts increases. The obtained results will help to further study the structural changes of binary and ternary mixed molten salts. © 2018, Editorial Board of Acta Energiae Solaris Sinica. All right reserved.