Interpreting an infrared (IR) spectrum without a sample present can be challenging since the purpose of an IR spectrum is to provide information about the functional groups and molecular vibrations present in a specific compound. Without a sample, there would be no specific compound or material to analyze, and thus the interpretation of an IR spectrum would be limited or impossible.
Infrared spectroscopy measures the absorption of infrared light by the sample, and different functional groups and molecular structures absorb at specific frequencies or wavenumbers. By comparing the absorption peaks in an IR spectrum to reference spectra or databases, scientists can identify the presence of certain functional groups or make educated guesses about the possible composition of a sample.
Without a sample, the absence of specific absorption peaks or bands in an IR spectrum would not provide any meaningful information. Additionally, the interpretation of IR spectra often involves comparing the observed peaks to known reference spectra or using additional analytical techniques to confirm the identity of compounds.
Therefore, while an IR spectrum may provide some general information about the range of frequencies or wavelengths being detected, it would not be possible to interpret the spectrum or make any meaningful conclusions about the composition or structure of a substance without a sample present.