Atomic and Molecular Emission Spectroscopy: A Laboratory Experiment for Undergraduate Students in Chemical Sciences

Beni Dangi

Nathaniel Carnegie

Florida A&M University

A laboratory experiment was designed for teaching laboratory aimed to teach students basics of spectroscopy. Despite the ubiquity of light-based tools in modern science, students often find it difficult to comprehend light and light-matter interactions. A portable spectrometer was utilized to record the emission spectra of various atomic and molecular samples in the visible range of the electro-magnetic spectrum. Three different wavelength laser sources were utilized to excite the molecular samples. Students record the experimental emission spectra from the lasers as well as provided inorganic and organic samples; and analyze spectra for emission wavelength, spectral peak widths and intensity. These experimental results help students to understand and appreciate the quantum theory of spectroscopy. Several conceptual and reasoning difficulties among students in relating the emission spectra to energy levels of atoms and molecules were reduced by laboratory activities and exercises. Furthermore, these laboratory activities can stimulate research interest in students as they look forward in their careers. Although the experiment is designed for a typical laboratory settings, it can be utilized in outdoor environments due to portable parts of the spectrometer that contains mini lasers, a mini spectrometer and a laptop computer.