Encouraging Student Engagement by Using a POGIL Framework for a Gas-Phase IR Physical Chemistry Laboratory Experiment

Abstract

A version of the classic rotationally resolved infrared (IR) spectrum of a diatomic molecule experiment has been developed using the POGIL framework to more fully engage students in the collection, modeling, analysis, and interpretation of the data. An analysis of the experimental protocol reveals that the POGIL approach actively engages students in scientific practices. The student learning objectives for this laboratory experiment are to (1) develop an energy level diagram and relate that diagram to rotational–vibrational spectra; (2) identify, describe, and interpret the molecular constants that can be extracted from gas-phase IR spectra; (3) discover the impact of spectral resolution on precision of molecular constants derived from the spectral data; and (4) use data to evaluate and refine quantum mechanical models. The learning cycles, analysis of student engagement with scientific practices, and reflections from instructors are described.

FTIR-SIS: A Fourier Transform Infrared Scientific Instrument Simulator

“…For more complicated molecules (asymmetric tops), third-party programs like PGOPHER or SPFIT/SPCAT could be used, or code could be developed in-house . Learning objectives of the analysis part of the lab will therefore vary somewhat, depending on the method used (e.g., see ref ). Learning objectives of the experimental part will also vary, depending on a number of considerations, such as the molecule that is under investigation and the parameters that students are encouraged to explore.…”

Determination of Stretching Frequencies by Isotopic Substitution Using Infrared Spectroscopy: An Upper-Level Undergraduate Experiment for an In-Person or Online Laboratory

“…39−44 Additional experiments that combine in-strumental methods and isotopic labeling have been reported 18,45,46 including ones that utilize vibrational spectroscopy such as the classic physical chemistry lab investigating the vibrational−rotational spectra of HCl and DCl. 17,22 Significantly, Ben-Amotz and co-workers published an experiment comparing experimental and theoretical results from Raman and IR measurements that includes vibrational studies of methanol and methanol-d 1 . 27 This experiment provides a rigorous demonstration of the use of isotopic labeling in peak assignment of the O−H stretch.…”

“…Vibrational spectroscopy is utilized across all chemical disciplines, and developing a strong understanding of the underlying chemical phenomenon, as well as an intuition for predicting expected experimental results, is an important skill for an undergraduate chemical education. Students often have their first introduction to infrared spectroscopy during an organic chemistry lecture or laboratory class where they learn to identify the characteristic stretching frequencies of functional groups, − and many laboratory experiments require students to utilize infrared (IR) spectroscopy to characterize a product they have prepared or identify an unknown substance. − This qualitative approach is typically expanded upon in inorganic, − physical, − and other upper-level , chemistry courses and laboratories that introduce the theoretical aspects of molecular vibrations and vibrational spectroscopy using a more mathematical or advanced approach. More recently, several experiments that utilize computations or simulations to allow students to explore molecular vibrations have been reported. ,,, …”

“…Isotopic labeling studies are commonly used by researchers to elucidate reaction mechanisms, − probe biological structure, − and facilitate spectroscopic analyses. − Although this is an important research tool, students often have limited lab experiences utilizing isotopes in experiments beyond deuterated NMR solvents, and to a lesser extent experiments that use isotopic labeling to probe kinetic isotope effects and mechanisms. − Additional experiments that combine instrumental methods and isotopic labeling have been reported ,, including ones that utilize vibrational spectroscopy such as the classic physical chemistry lab investigating the vibrational–rotational spectra of HCl and DCl. , Significantly, Ben-Amotz and co-workers published an experiment comparing experimental and theoretical results from Raman and IR measurements that includes vibrational studies of methanol and methanol-d 1 . This experiment provides a rigorous demonstration of the use of isotopic labeling in peak assignment of the O–H stretch.…”

Experiences with an Inquiry-Based Ionic Liquid Module in an Undergraduate Physical Chemistry Laboratory

“…Instructors can use an inquiry-based lesson with a traditional class discussion to present new information or clarify the underlying principles of the laboratory explorations. 25 The POGIL workflow reported for physical chemistry laboratory (PCL) courses, the POGIL-PCL model, 26,27 along with other related POGIL activities 23,28 in the physical chemistry laboratory provide pathways for designing inquirybased laboratory modules on ionic liquids. However, executing the POGIL workflow as reported in the literature in the laboratory for ionic liquids is difficult for two reasons: (a) ionic liquid is not taught as a topic in the chemistry curriculum at Xavier University of Louisiana, which we assume is true for many other universities and (b) the characteristics of these liquids are not similar to traditional solvents which the students are accustomed to in their curriculum, particularly in laboratory practices.…”