I was at home from AAS 240 for about 21 hours before I left for the airport, this time to fly to the Midwest. Today was the first day of the 75th International Symposium on Molecular Spectroscopy (ISMS), known affectionately as the “donut conference” for the mountain of donuts stocked in the library of the chemistry building on the University of Illinois at Urbana-Champaign (UIUC) campus.

Once again, I’ve brought my sketchbook and colored pencils to sketch summaries of the talks I attend. Here’s the illustrated summaries from Day 1! (You can also find them on Twitter via #SciConSketch.)

Plenary (Session MA)

Theoretical Descriptions of the Fundamentals of CH, NH, and OH Stretch Vibrations with Simple Models that Include Anharmonic Effects — Edwin Sibert (University of Madison)

The first talk of the day consisted of six vibrational vignettes: energy flow (which talked about the use of statistical energy diagrams); the formic acid (HCOOH) monomer (comparing the perturbations of its two conformational states); peptide conformation preference (determined by high-resolution spectroscopy of large biomolecules); identifying alkylbenzene via UV, IR, and Raman spectroscopy; the interconversion of equatorial and axial orientations of CH in ring molecules via pseudo-rotation; and NH stretch vanishing acts (which asked how hydrogen bonding affects the N-H stretch in large molecules).

Chemistry in the Ultracold Regime: Precision Molecular Assembly and Test of Statistical Reaction Dynamics — Kang-Kuen Ni (Harvard University)

The second plenary started with a brief overview of quantum before talking about how ultracold molecules can be used as “quantum bits,” or qubits in which rotational modes and accompanying hyperfine states of a molecule constitute different qubits. The talk provided an overview of the technique used to form one molecule at a time. Such a feat is possible via laser cooling, and laser light of different wavelengths enable trapping of individual atoms by “optical tweezers.” Surprisingly, using “optical tweezers” isn’t the hardest part of the work discussed. Rather, binding the selected atoms is! Forming bonds is a two-step process: 1. weakly bond the atoms, and 2. shrink the distance between the atoms to form a stronger bond.

Vibrational Spectral Signatures and Dynamics of Strong Intramolecular H-Bonds Investigated with Gas-Phase Ion and Solution-Phase Ultrafast Infrared Spectroscopies — Joseph Fournier (Washington University at St. Louis)

The third plenary talk discussed how gas-phase ion and ultrafast solution-phase infrared (IR) spectroscopies can be highly complementary. Specifically, it talked about a combination of three techniques, namely cryogenic ion vibrational spectroscopy (CIVS), solution-phase transient absorption and 2D IR, and time-resolved CIVS.

New Frontiers in Cosmic Carbon Chemistry — Brett McGuire (MIT)

The fourth plenary was about astrochemistry. It started off by talking about how 80% of compounds in the CAS database (CAS is a division of the American Chemical Society) contain 5- or 6-membered rings, but not many ringed species have been found in space. The question, then, is where are such ringed species in space? The first ring (benzene) was discovered in 2001. It wasn’t until 2018 that the next one was discovered; since 2018, 9 more ringed molecules have been found. Despite not knowing what ringed structures are out there, we know that there is a lot of aromatic carbon (thanks to the diffuse interstellar bands, represented by the lumpy red spectrum in the center of the sketch), but the IR features of such molecules overlap, making it difficult (impossible?) to identify them in the IR. BUT rotational spectra can be resolved and are unique for different cyclic compounds. Using the GBT, benzonitrile was detected in TMC-1 (TMC = Taurus Molecular Cloud), and it was also found (again with the GBT), in several molecular cores in Serpens. Studying such complex species requires lab work and theory (including machine learning).

After Brett’s talk, I needed to give my brain a break (and my phone a charge), so I grabbed some pizza, headed back to my hotel room, picked up a couple of postcards (one for Alex and Gueni, one for a friend I unsuccessfully tried to convince to come to the conference), and stopped by a postbox before heading to my afternoon session.

Astronomy (Session MN)

NOEMA Observations of Complex Organic Chemistry in the W3 Star-Forming Region — Will Thompson (University of Wisconsin-Madison)