This article suggests that when introducing the topics associated with absorption spectroscopy, the students can greatly benefit from a preliminary discussion of the principle of frequency matching. Virtually all types of absorption spectroscopy share a simple but critical requirement: the frequency of absorbed radiation must exactly match the frequency of some inherent or induced periodic motion of the particles. If the particles are not engaged in such motion, there can be no absorption. This principle is a straightforward consequence of the necessity for the electric or magnetic oscillations of the incident radiation to match in both frequency and orientation (polarization) the characteristic electric or magnetic oscillations of the particles absorbing the radiation in order for constructive interference, resonance, and energy exchange to occur. Three of the most common types of spectroscopy (vibrational, electronic, and nuclear magnetic resonance) are discussed as examples of this principle.
Our Secondary School editors work hard to distill all the JCE materials to produce a fraction of particular interest to high school teachers. We call it CLIC.
In recent years we have worked hard to better match our advertisers with our readers. When shopping for chemistry education materials, visit our advertisers' WWW sites first.
Take JCE along on your outreach missions. Copies of the Journal, guest access to JCE Online, our publications catalog, and more are available for your participants.