Nitrous oxide / acetylene flame overview spectra

Figure 7.10 Overview spectrum of A1 in a nitrous oxide / acetylene flame with bands of AlCl and AlH (sample 5g/L A1 as AICI3 dissolved in 1 % v/v HNO3 reference deionized H2O)...

Using the standard air / acetylene flame and hydrofluoric acid a different diatomic aluminum molecule is formed. Now, AIF becomes visible, as seen in the overview spectrum of Figure 7.11 and the enlarged clipping in Figure 7.12. In comparison to the other two A1 molecules measured in the nitrous oxide / acetylene flame, this band system is not so fine structured. It results from a Av = 0 sequence of the X A 11 electronic transition around 227.5 nm. 

Figure 7.17 Overview spectrum of a nitrous oxide/acetylene flame with bands of NO, OH, NH, CN, and an unknown molecule (sample flame turned on reference flame turned off)...

It has already been mentioned in Section 7.2.6 that the nitrous oxide/acetylene flame itself, apart from CN and NO bands, produces NH molecule structures. They are present in the wavelength region around 336 nm (refer to overview spectrum in Figure 7.17 and the enlarged clipping in Figure 7.30). The corresponding electronic transition with a Av = 0 sequence connects the X to the A H state. 

Due to the presence of carbon, hydrogen, nitrogen and oxygen, the nitrous oxide (N2O)/ acetylene (C2H2) flame itself produces a lot of different diatomic molecule structures as can be seen in the overview spectrum of Figure 7.17. They are present all the time using this kind of flame and therefore special attention should be paid to them since they can increase the BG noise level. 

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