The goal of this document is to present a systematic
development of the relationship between spectroscopic
experiments and the determination of molecular bond lengths
in the excited state of diatomic molecules for which a high
resolution vibronic spectrum is available. This document can
serve as a template for students to use for data analysis of the
UV-vis spectrum of I2 or other diatomic gases. Use of this
document as a template requires student UV-vis spectral data
acquired in the laboratory. Faculty can also use this
document with the enclosed sample data for student practice when
an instrument is not available. The details of the
Birge-Sponer plot are clearly illustrated.
The document discusses the
Morse potential and includes calculations with
this potential function using correct units.
Students can see clearly the mathematical steps leading to the
calculation of the equilibrium bond length of the
excited state of iodine. The Morse potentials for both the
ground state and excited state permit discussion of
the effect of excitation on molecular geometry. This document represents
a way to make data analysis
and work with the concepts for this experiment more
efficient for students. Student exercises are fully integrated into
the presentation and implementation of the mathematical
concepts of this topic. References for the laboratory
experiment are included.
Ground and excited electronic
state Morse potentials from
IodineSpectrum.mcd.
More Information
Citation
Long, George; Zielinski, Theresa Julia. J. Chem. Educ.1998 75 1192.
Keywords
teaching, learning aids, physical chem, quantum chem, internet
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.