Most IR spectral tables tend to be focused around "typical" bonds found in organic chemistry, hence your signal is listed as one of the dozens of possible carbon bond structures. While I am unable to give you a direct asnwer as to the peak, not knowing what types of atoms are in the composite, I can provide a few hints that can help you find the answer out:

1. What is the spectral resolution of your FTIR setup? While the program may list a data point at 607 cm-1, with a spectral resolution of 2-3cm-1 (typical) your signal could be anywhere from 605 to 610 cm-1. Moreover, the table values do not always include all possible factors, affecting the oscillator strength of the bond. As such, do not try for a perfect fit, but consider characteristic signals that are in the range of, let's say, 587-627cm-1 (or even wider!).

2. Repeat the experiment several times for different smaples of the composite and check whether the peak is reproducible, in order to rule out the possibility of a contaminant. This is particularly the case for ATR FT IR setups, as traces of a previous sample may have been left on your ATR crystal.

3. Record the spectra of each pure component of your composite and check whether the signal is present in any of them. If so, you can narrow down the range of possible transitions. If not, the "culprit" arises from interactions within the composite and a prediction of the reactions between the components will be necessary (and will be verified by identifying the source of this signal and the presence / lack of other expected signals).

Thanks a lot Sir.

You're welcome! Please let me know if you need any further assistance.