The existence of characteristic energy levels for different [[chemical substance]]s is useful for their identification by the analysis of [[spectral lines]] of different kinds of spectra often used in chemical spectroscopy e.g. [[infrared spectroscopy|IR]], [[microwave spectroscopy|microwave]], [[NMR]], [[electron spin resonance|ESR]] etc. This is used to identify the composition of remote objects - like stars and far galaxies - by analyzing their radiation (see [[spectroscopy]]). | The existence of characteristic energy levels for different [[chemical substance]]s is useful for their identification by the analysis of [[spectral lines]] of different kinds of spectra often used in chemical spectroscopy e.g. [[infrared spectroscopy|IR]], [[microwave spectroscopy|microwave]], [[NMR]], [[electron spin resonance|ESR]] etc. This is used to identify the composition of remote objects - like stars and far galaxies - by analyzing their radiation (see [[spectroscopy]]). |