Hi Kalyan, your organic molecule structure is unknown to me, maybe your molecule has more than one chromophor therefore there will be more than one band. if you are sure that there must be one band and you observed more , first make sure your solvent is pure if it is pure then change the solvent and see,after that look for possibility of charge transfer formation within the molecules good luck

Compare your data to the donor and acceptor moeities alone and check your new peak

Hi Kylan,

From the experimental point of view, CT bands normally shift with solvent polarity (solvatochomism) which is a good indication.

From the computational point of view, you can calculate the HOMO and LUMO. If you have a CT band, there should be a significant shift of electron density from the donor to the acceptor.

Hi Kalyan. Indeed solvatochromism will give you some clues about charge transfer. Also, please check whether your probe has any phenolic groups. They often results a bath chronically shifted absorption peak due to partial deprotonation. Depending on the solvent, the intensity of this absorption peak can be different. For example polar aortic solvent like DMSO will promote further deprotonation.

If this is not the case, the another option to analyze your probe under different pH environments. This will give you more clues definitely.

Also my preferred solution for this situation really is to analyze low temperature excitation and fluorescence spectra if you have the access to the instrument.

I will be able to give you a better explanation if I can see the probe structure.

Hope this will help and Good luck!!!

CT emission band is (1) red shifted as compared to LE emission band (2) structureless (3) varies with the solvent polarity.

1) Compare the spectrum with individual donor acceptor reactants.

2) Perform the same with different solvents as formation of CT complex depends on polarity of the solvent.

3) Red shift can be noticed.

4) Appearance of new peak indicates complication.

(Take FTIR of reactants and CT complex individually to compare)

You can use TD-DFT calculations for theoretician verification.

Article Preparation, single-crystal investigation and spectrophotome...

d-d transition of octahedral complexes are forbidden due to symmetry according to Laporte rules. Though we get absorption band due to vibronic coupling. But this band absorption is less intense whereas absorption for CT transition is more intense. So we can distinguish d-d & CT transition from this idea. Further if you calculate molar extinction coefficient then higher value of coefficient indicates CT transition.