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Dual Comb Spectroscopy with Mismatched Combs

Dual comb spectroscopy is a high-resolution technique that requires two frequency combs with very similar spectral characteristics. Most examples of dual comb spectroscopy in the literature use two lasers with the same architecture. Dual comb spectroscopy is a comb tooth resolved technique, which means the frequency resolution is generally less than 100 kHz, however these comb teeth are spaced MHz to GHz apart. Some literature examples try to…


Probing the Formation of Carbon Particles with Laboratory and Synchrotron Experiments

Gas phase nanoparticle formation is a highly complex process that transforms small molecules and radicals into solids that impact many aspects of our lives. These impacts may be positive (high value materials, commodity chemicals etc.) or negative (pollutants). Developing robust chemical mechanisms describing the formation of nanoparticles is critical to controlling the formation of desired species and the optimization of processes. Production…


Convergent Ab Initio Analysis of the Multi-Channel HOBr + H Reaction

High-level potential energy surfaces for three reactions of hypobromous acid with atomic hydrogen were computed at the CCSDTQ/CBS//CCSDT(Q)/complete basis set level of theory. Focal point analysis was utilized to extrapolate energies and gradients for energetics and optimizations, respectively. The H attack at Br and subsequent Br–O cleavage were found to proceed barrierlessly. The slightly submerged transition state lies −0.2 kcal mol−1…


Formation and Dissociation of Hydrocarbons Under Interstellar Conditions

Hydrocarbons of all shapes and sizes are found throughout the various stages of star- and planet formation. Recently, using radio astronomical observations, a variety of cyclic- and even polycyclic hydrocarbons have been detected in the very cold (10 K) Taurus molecular cloud. These detections challenge our understanding of the chemical formation mechanisms under these low-temperature and low-density conditions. In photon-dominated regions…


Plasma-Assisted Catalysis for Ammonia Synthesis

Ammonia (NH3) is important in the production of many products including fertilizers, plastics, resins, synthetic fabrics, and explosives. At the industrial scale, NH3 is produced using the Haber–Bosch (H–B) process, which is typically carried out at high temperatures and pressures. This process produces over 300 million metric tons of carbon dioxide each year, and consumes 1-2% of the world’s energy supply. Plasma catalysis is emerging as a…


Excitation of Molecules Using Scanning Tunneling Microscopy

Scanning Tunneling Microscopy (STM) has been a powerful method of imaging surfaces with very high spatial resolution. Another important use of STM is the study of molecular reaction pathways brought about by inelastic electron tunneling. In this process, tunneling electrons containing energy above a threshold bring about an excitation in the molecular system which leads to reaction pathways as the excited molecule consequently relaxes along its…


Building a Higher Sensitivity Two-Dimensional Spectrometer

Ultrafast Two-Dimensional (2D) Spectroscopy is a powerful technique that has provided valuable insight into diverse systems from protein folding to isomerization of metal complexes. We aim to bring this technique to the realm of small molecules in molecular beams. 2D spectroscopy is unique because it allows for the direct measurement of coupled excitations, represented by off diagonal peaks within the spectra. However, because 2D spectroscopy is…


Unraveling the Mechanism of Magnetoreception: Inspecting the Electron Transfer Cascade in Cryptochrome

Magnetoreception plays a key role in the migration of the European robin. Cryptochrome (Cry) is believed to be responsible for the ability of these birds to detect the direction of the geomagnetic field during migration. A cofactor of cryptochrome, flavin adenine dinucleotide (FAD) absorbs blue light, resulting in a ᴨ to ᴨ* transition. In this ᴨ* excited state, FAD is the recipient of four consecutive electron transfers along a tryptophan (Trp)…


In-Source High-Resolution Spectroscopy Using an Integrated Tunable Raman Laser

Raman Lasers are an interesting option for Resonance Ion spectroscopy. They rely on a Raman transition which is not limited by bound transition. This work demonstrates Raman lasers ability to be used for high resolution spectroscopy to observe atomic transitions. 


Frequency Combs as the Route to the Spectroscopic Trifecta: High Time Resolution, High Frequency Resolution, and High Sensitivity

Many consequential chemical processes take place on ultrafast timescales, including molecular vibrations and bond breaking. Measurements that follow ultrafast molecular dynamics in real time are changing our understanding of these processes. We are designing new tools to study ultrafast molecular dynamics and quantum mechanics with the sensitivity enough to study the molecules in molecular beams and the spectral resolution sufficient for…
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