Suppose I have emission centred at 615 nm for europium complex,then for that other than 396nm there is a peak at 308nm,due to second harmonics.But I am not sure why this is occurring..
but sir what if I am getting this for only one liquid sample? For other samples I am not getting this harmonic.
You should use a filter to block stray light. You can check the emission by varying the temperature.
To make sure if your signal is multiple of wavelength, you can simply check that by changing the excitation wavelength.
Excite the sample with 275nm and check whether u get the same emission, in my opinion this peak at 308nm should not be observed if excited at 375nm. If you still observe then they may have contamination of Gd3+.
Higher harmonics come from the diffraction grating which allows different integral multiple of a wavelegnth at the same angle.
Atul Khanna This is the only correct answer here. There is always this harmonic in excitation or emission spectra. Just to be sure that there is no an absorption peak do as Baichhabi Raj Yakami said.
The harmonics are mainly from the grating system we used during measurements. For Eu3+, 615 nm :excitation spectra (200-590 nm), you can choose 360 nm cut-on filter.
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