High temperature infrared spectrum of sodium iodide (NaI)

摘要

The absorption spectrum of sodium iodide vapor between 200 and 275 cm(-1) has been measured with a resolution of 0.006 cm(-1) at a temperature of 1096 K. The Delta nu = 1 transitions from nu = 1 <- 0 to nu = 13 <- 12 have been measured. Dunham constants are given from an least-squares analysis of 1285 fairly well resolved transitions. The band center for the fundamental band is nu(0) = 257.2837 +/- 0.0002 cm(-1). The relative intensities of the Delta nu = 1 transitions from different vibrational states are studied and it is shown that the intensity is roughly proportional to nu '' + 1 as expected from the harmonic oscillator approximation. From measurements of the Herman-Wallis constant, alpha(1,0) = -0.0054 +/- 0.0008, it is estimated that the transition moment must be mu(1.0) approximate to 0.135 0.020 debye. (C) 2014 Elsevier Inc. All rights reserved.