Undergraduate research is considered the best pedagogical practice for engaging chemistry students in their curriculum and encouraging independent problem-solving. This presentation will explore many aspects of the undergraduate research experience in chemistry, beginning with the author’s efforts in constructing instruments and conducting matrix-isolation FTIR experiments with undergraduate students. To expand the impact to more students and increase their exposure to modern physical chemistry research, journal club sessions have been brought to the classroom. Finally, a faculty-created, comprehensive summer research program and large group trips to national meetings have helped chemistry majors understand how their independent research advances not only the field of chemistry but also their professional development.

The cyclohexadienyl radical (C₆H₇) was observed in a low temperature argon matrix with matrix isolation infrared spectroscopy. The C₆H₇ radical was produced from the reaction of H atoms with benzene (C₆H₆) in the argon matrices. The H atoms were produced by either vacuum ultraviolet (VUV) photolysis or direct microwave discharge of H₂S in argon and co-deposited with C₆H₆ in the argon matrices. The most intense peak of the C₆H₇ radical was observed at 621.0 cm⁻¹, with several other weaker peaks observed at 512.0, 865.9, 910.9, 961.2, 973.7, 1290.3, 1390.2, 1394.9, 1425.9, 2758.7, and 2781.3 cm⁻¹. The yield of the C₆H₇ radical was found be approximately 40 percent larger for the direct microwave discharge experiments as compared to the VUV photolysis experiments. The identification and assignment of the C₆H₇ radical peaks was accomplished by comparisons to co-deposition spectra without VUV photolysis or direct discharge, the H₂S and C₆H₆ monomer spectra with and without VUV photolysis/direct discharge, filtered (400 - 900 nm) and unfiltered Hg-Xe lamp photolysis, and 35 K annealing. Experiments were also performed in which H atoms were reacted with C₆D₆ producing the C₆D₆H radical, with peaks observed at 460.0, 747.8, 830.0, 1237.5, 1245.5, 1246.7, and 2792.0/2796.8 cm⁻¹. Quantum chemistry calculations for the C₆H₇ radical were performed at the DFT and MP2 levels of theory with the aug-cc-PVTZ basis set to obtain the theoretical infrared spectrum to support the assignments. The peaks of the C₆H₇ radical observed in argon matrices are in good agreement with the values reported in xenon matricesV. I. Feldman, F. F. Sukhov, E. A. Logacheva, A. Y. Orlov, I. V. Tyulpina, and D. A. Tyurin, Chem. Phys. Lett. 437, 207 (2007)nd para-hydrogen matricesM. Bahou, Y. J. Wu, and Y. P. Lee, J. Chem. Phys. 136, 154304 (2012)

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V. I. Feldman, F. F. Sukhov, E. A. Logacheva, A. Y. Orlov, I. V. Tyulpina, and D. A. Tyurin, Chem. Phys. Lett. 437, 207 (2007)a M. Bahou, Y. J. Wu, and Y. P. Lee, J. Chem. Phys. 136, 154304 (2012).

Students taking physical chemistry often find the thermodynamics section of the course confusing and even downright uninteresting. In part, this is due to the abstract nature of concepts, such as entropy and enthalpy, as well as the math skills that are required and/or the transference of skills that students already possess. An activity was created and implemented for use in an undergraduate physical chemistry course to guide students through an application of thermodynamics through the lens of spectroscopy. The activity combines current spectroscopic research techniquesLeavitt, C. M.; Moore, K. B.; Raston, P. L.; Agarwal, J.; Moody, G. H.; Shirley, C. C.; Schaefer, H. F.; Douberly, G. E. Liquid Hot NAGMA Cooled to 0.4 K: Benchmark Thermochemistry of a Gas-Phase Peptide. J. Phys. Chem. A 2014, 118 (41), 9692–9700.ogether with concepts covered in class to give students a complete picture of this topic. In this talk, the activity and its implementation will be discussed along with preliminary outcomes.

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Footnotes:

Leavitt, C. M.; Moore, K. B.; Raston, P. L.; Agarwal, J.; Moody, G. H.; Shirley, C. C.; Schaefer, H. F.; Douberly, G. E. Liquid Hot NAGMA Cooled to 0.4 K: Benchmark Thermochemistry of a Gas-Phase Peptide. J. Phys. Chem. A 2014, 118 (41), 9692–9700.t

Weakly-bound complexes containing aromatic species have been the subject of study for many years. Here, a study of the weakly-bound complexes of selenophene () with water will be presented. In this study, matrix isolation FTIR and computational methods were used to examine stable 1:1 complexes of selenophene : water (Sp:). Multiple density functional theories along with MP2 calculations were used to find a total of seven stable geometries which could be sorted into four categories defined by the intermolecular forces observed in the complex. The interactions include , , and . The Sp: geometries were found to be within 16 kJ/mol of each other across all computational methods. All calculated structures were similar to those found for complexes of furan : water and thiophene: water. Matrix isolation FTIR experiments identified several peaks that were not associated with isolated water or selenophene, implying the bands are due to weakly-bound complexes of the two monomers. In addition to normal water, and HDO complexes with selenophene were also observed. Possible interpretations of the experimental and computational results will be presented.

A home-built helium nanodroplet isolation spectrometer has been utilized by undergraduate students in course-based experiments to investigate the rovibrational dynamics of small molecules. Helium nanodroplets are well known to simplify the spectroscopy of embedded molecules owing to their low temperature (0.4 K) and weakly interacting nature. In the infrared spectral region, this results in a small number of rotationally resolved lines that can often be collected and analyzed in several lab periods. We demonstrate the advantages of using this technique in an upper-level undergraduate chemistry course for which the laser spectroscopy of helium solvated ¹³C-labelled formic acid was investigated for the first time.

Saturn’s moon Titan exhibits the most complex and diverse atmospheric chemistry of any body in the solar system other than the Earth. Photochemistry in the upper atmosphere starts with methane and nitrogen and produces a rich array of hydrocarbons and nitriles, and also some oxygen compounds due to an external oxygen source from Enceladus. Since the 1970s, infrared spectroscopy has been the primarily mechanism for probing the composition of the neutral atmosphere, using ground-based telescopes, visiting spacecraft such as Voyager and Cassini, and space-based observatories including the Infrared Space Observatory (ISO) and Herschel. We present for first time infrared spectra from the Spitzer space telescope (2004-2009) in both the short wavelength-low resolution channels (SL, R ∼ 60−127, 5.13 to 14.29 microns) and short wavelength-high resolution channels (SH, R ∼ 600, 9.89 to 19.51 microns) showing the emissions of CH4, C2H4, C2H2, C2H6, HCN, CO2, HC3N, C3H4 and C4H2. We compare the results obtained for Titan from Spitzer to those of ISO, Herschel and Cassini CIRS, and comment on the effect of spectral resolution on retrieved information content. We conclude by recommending gaps in current spectroscopic knowledge of molecular bands that could be addressed by theoretical and laboratory study to aid future astronomical studies of Titan.

Diethyl phthalate (DEPh), a diethyl ester of phthalic acid, is commonly used as a plasticizer in products such as plastic packaging films, toiletries, and plastic bags.¹ The two ester groups can rotate about the respective single C – C bonds, making the conformational landscape of DEPh quite complex, and further investigation may improve our knowledge about the conformational landscape and dynamics of DEPh. Additionally, the close proximity of the two substituent groups and the resulting non-covalent interactions that will occur between them will ultimately dictate the monomeric structure. A thorough experimental investigation and assignment of the DEPh conformers may not only provide valuable insights into non-covalent intramolecular interactions, but also valuable conformational benchmark data for theory. We use rotational, microwave, spectroscopy to experimentally probe the conformational diversity of DEPh, as it has been shown before to be an excellent tool to investigate conformationally flexible molecules.² A broadband rotational spectrum was recorded in the 2-6 GHz region using a chirped pulse Fourier transform microwave spectrometer (CP-FTMW). With the help of the Conformer-Rotamer Ensemble Sampling Tool (CREST)³ and DFT calculations, we identified 16 unique theoretical conformers. Using these results as an assignment aid, a total of 7 conformers were identified in our rotational spectrum. Non-covalent interactions (NCI)⁴ analyses were carried out to examine the intermolecular interactions present within the DEPh conformers. 1. J. Sekizawa, S. Dobson, R. J. Touch III, DIETHYL PHTHALATE, CICAD. 2003;2. F. Xie, N. A. Seifert, M. Heger, J. Thomas, W. Jäger, Y. Xu, Phys. Chem. Chem. Phys. 2019. 21, 15408-16.; 3. P. Pracht, F. Bohle, S. Grimme, Phys. Chem. Chem. Phys. 2020., 22, 7169-7192; 4. E. Johnson, S. Keinan, P. Mori-Sánchez and J. Contreras-García, J. Am. Chem. Soc., 2010, 2010, 132.;

As a representative of the next-generation solar cells, dye-sensitized solar cells (DSSCs) offer the efficient and ease of implementation of new technology for future energy supply. Herein, four commercially available dyes including, curcumin, betanin, crystal violet, methylene blue, their compositions, and two naturally extracted dyes were used as sensitizers for fabrication of titanium oxide photo-anode based DSSCs. All dyes were fully characterized using absorption and emission spectroscopy. Both DFT and TDDFT studies were also carried out to probe the electronic structure of these dyes. The power conversion efficiencies of each DSSCs prepared using the individual and composited dyes were measured and compared. Particularly, this is the first study to combine four different dyes for DSSCs, leading to a remarkable increase of power conversion efficiency. The DSSCs with combined curcumin, betanin, crystal violet, and methylene blue (in 1:1:1:1 respectively) in ethanol exhibited the highest power conversion efficiency of 3.62%.

A new compression algorithm for the efficient storage of molecular line lists has been recently presentedR. J. Hargreaves, I. E. Gordon, M. Rey, A. V. Nikitin, V. G. Tyuterev, R. V. Kochanov, L. S. Rothman, Astrophys. J. Suppl., 2020, 247, 55. The algorithm is based on the effective `super-energies' developed to produce a compact HITEMP line list for methane. This method assumes a set of artificial lower state (super-)energies and corresponding reference intensities for an approximate description of the temperature dependent molecular absorption (absorption coefficient) on a grid of wavenumbers. The super-energies compression is applied only to the majority ( > 99%) of the lines representing the weaker, continuum part of the molecular absorption, while the strongest lines ( < 1%) are preserved in the original form to maintain the accuracy of the line list. Here we adopt and develop the HITEMP compression algorithm to be applicable to the ExoMol data format and generate new compressed line lists for SiO<sub>2</sub>,A. Owens, E. K. Conway, J. Tennyson, S. N. Yurchenko, Mon. Not. R. Astron. Soc., 2020, 495, 1927-1933.<sub>2</sub>O,O. L. Polyansky, A. A. Kyuberis, N. F. Zobov, J. Tennyson, S. N. Yurchenko, L. Lodi, Mon. Not. R. Astron. Soc., 2018, 480, 2597-2608.OH and NaOH.A. Owens, J. Tennyson, S. N. Yurchenko, Mon. Not. R. Astron. Soc., 2021, 502, 1128-1135.e find that using artificial Einstein A coefficients instead of reference intensities provides a more accurate description of the temperature dependence. A typical compression of a line list consisting of, e.g., 40 billions SiO<sub>2</sub> lines is to about 40 million data points. Advantages and limitations of the `super-energies' approach will be discussed. The compressed molecular line lists will be included in the ExoMol database ( WWW.EXOMOL.COM) and their use should greatly facilitate atmospheric retrievals in exoplanets and other hot astronomical bodies.

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Footnotes:

R. J. Hargreaves, I. E. Gordon, M. Rey, A. V. Nikitin, V. G. Tyuterev, R. V. Kochanov, L. S. Rothman, Astrophys. J. Suppl., 2020, 247, 55.. A. Owens, E. K. Conway, J. Tennyson, S. N. Yurchenko, Mon. Not. R. Astron. Soc., 2020, 495, 1927-1933.H O. L. Polyansky, A. A. Kyuberis, N. F. Zobov, J. Tennyson, S. N. Yurchenko, L. Lodi, Mon. Not. R. Astron. Soc., 2018, 480, 2597-2608.K A. Owens, J. Tennyson, S. N. Yurchenko, Mon. Not. R. Astron. Soc., 2021, 502, 1128-1135.W

Ï get to help find aliens" - what better motivation for high school students getting into research for the first time! The identification of molecular biosignatures on exoplanets is a powerful example of the diverse role of spectroscopy in science that strongly motivates student interest and understanding of the fundamental principles of spectroscopy and its applications. r0pt Figure Though of course, the scientific journey to actually finding exoplanet molecules, particularly biosignatures, is long and far beyond the scope of current high school or undergraduate student projects, we can involve students in this journey. In my research, I focus on molecular spectroscopic data production computationally. In this presentation, I briefly describe how I involve students in this research project and identify good practice recommendations and common challenges. I focus on two programs involving high-school students in scientific research, the first as collaborators and publication co-authors (ORBYTS, UK, twinkle-spacemission.co.uk/orbyts/) and the second as independent researchers (SciX@UNSW, Australia, http://unsw.to/scix). I will also discuss how this research area can be used to motivate deep outreach engagement (Depth Studies, UNSW, Australia) and as the venue for small publishable undergraduate projects.

We describe an exercise for the undergraduate teaching lab that uses EPR spectroscopy to determine the g and D values for the chromium(III) ion in a ruby ball lens. Students use a polarized light stereomicroscope to identify the ruby c-axis; once found, ruby orientation is locked in place with a teflon screw at the end of a teflon post. The post can then be rotated in the magnetic field of an X-band EPR spectrometer using an inexpensive rotation platform. Spectra are obtained from 0 to 90 degrees in 5 degree increments; the result is a huge amount of data, which is more easily handled using Igor Pro software.¹ Resonance field positions are found and plotted as a function of angle, and the values of g and D are determined from the 0^° spectrum.² Using their experimental g and D values, students diagonalize the spin Hamiltonian using a procedure written in Igor Pro. Calculated resonance field positions at each angle can then be compared with experimental results. 1. WaveMetrics, Inc. 10200 SW Nimbus, G-7 Portland , OR 97223 2. L.A. Collins, M.A. Morrison, P.L. Donoho Am. J. Phys., 42 (1974) 560-571.

Based on discussions and suggestions received during the "Spectroscopy in the Classroom" 2015 ISMS mini-symposium, I have implemented guided-inquiry based spectroscopic projects in the upper-level undergraduate physical chemistry lab course. In this course, the first half of the semester is now primarily devoted to gaining familiarity with spectrometers and computational chemistry, and the second half is devoted towards students projects, with 3-4 weeks devoted to characterization of a student-chosen compound and 3-4 weeks to student-designed experiments on that compound. Time is built into the schedule for student experiments to fail, be revised, and be attempted again with the revised procedure. This talk will describe how this approach works in practice in our local context, where both chemistry and biochemistry majors take the course but biochemistry majors do not generally take quantum mechanics. Examples of student feedback will be provided as well as reflection about the strengths and weaknesses of this approach.

Developing and building a research program in spectroscopy at a primarily undergraduate institution is a challenging and rewarding experience. In this talk, I will discuss my personal experience developing a research program in infrared spectroscopy applied to atmospheric chemistry at Connecticut College, a small liberal arts college located in the northeast of the United States. Working with undergraduate students in a research setting provides an excellent opportunity to mentor students one-on-one, but also comes with challenges related to student time and expertise. I will present strategies that I have found useful in addressing the unique needs of undergraduates performing research in molecular spectroscopy.