A5015377066- Atmospheric Ozone and Climate
- Astrophysics and Star Formation Studies
- Molecular Spectroscopy and Structure
- Spectroscopy and Laser Applications
- Advanced Chemical Physics Studies
- Crystallization and Solubility Studies
- Fullerene Chemistry and Applications
- Astro and Planetary Science
- Analytical Chemistry and Chromatography
- Atmospheric chemistry and aerosols
- Advanced Data Processing Techniques
- Crystallography and molecular interactions
- Inorganic Fluorides and Related Compounds
Massachusetts Institute of Technology
2023-2024
Macalester College
2020
Hydrofluoroolefins are being adopted as sustainable alternatives to long-lived fluorine- and chlorine-containing gases finding current or potential mass-market applications refrigerants, among a myriad of other uses. Their olefinic bond affords relatively rapid reaction with hydroxyl radicals present in the atmosphere, leading short lifetimes proportionally small global warming potentials. However, this type functionality also allows ozone, whilst these reactions slow, we show that products...
Polycyclic aromatic hydrocarbons (PAHs) are organic molecules containing adjacent rings. Infrared emission bands show that PAHs abundant in space, but only a few specific have been detected the interstellar medium. We 1-cyanopyrene, cyano-substituted derivative of related four-ring PAH pyrene, radio observations dense cloud TMC-1, using Green Bank Telescope. The measured column density 1-cyanopyrene is <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"...
Polycyclic aromatic hydrocarbons (PAHs) are among the most widespread compounds in universe, accounting for up to ~25% of all interstellar carbon. Since unsubstituted PAHs do not possess permanent electric dipole moments, they invisible radio astronomy. Constraining their abundances relies on detection polar chemical proxies, such as nitriles. Here we report 2-cyanopyrene and 4-cyanopyrene, isomers recently detected 1-cyanopyrene. We find that these present an abundance ratio ~2:1:2, which...
Abstract We report the detection of lowest-energy conformer E -1-cyano-1,3-butadiene ( -1- <?CDATA ${{\rm{C}}}_{4}{{\rm{H}}}_{5}\mathrm{CN}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi mathvariant="normal">C</mml:mi> </mml:mrow> <mml:mn>4</mml:mn> </mml:msub> mathvariant="normal">H</mml:mi> <mml:mn>5</mml:mn> <mml:mi>CN</mml:mi> </mml:math> ), a linear isomer pyridine, using fourth data reduction GBT Observations TMC-1: Hunting...
Abstract We present the spectroscopic characterization of cyclopropenethione in laboratory and detect it space using Green Bank Telescope Observations TMC-1: Hunting Aromatic Molecules survey. The detection this molecule—the missing link understanding C 3 H 2 S isomeric family TMC-1—completes all three low-energy isomers S, as both CH CCS HCCCHS have been previously detected source. total column density molecule ( N T <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"...
Abstract We use both chirped-pulse Fourier transform and frequency-modulated absorption spectroscopy to study the rotational spectrum of 2-methoxyethanol (CH 3 OCH 2 CH OH) in several frequency regions ranging from 8.7 500 GHz. The resulting parameters permitted a search for this molecule Atacama Large Millimeter/submillimeter Array (ALMA) observations toward massive protocluster NGC 6334I, as well source B low-mass protostellar system IRAS 16293−2422. A total 25 transitions are observed...
Machine learning techniques have been previously used to model and predict column densities in the TMC-1 dark molecular cloud. In interstellar sources further along path of star formation, such as those where a protostar itself has formed, chemistry is known be drastically different from that largely quiescent clouds. To end, we tested ability various machine models fit molecules detected source B Class 0 protostellar system IRAS 16293-2422. By including simple encoding isotopic composition...
Abstract We used new high spectral resolution observations of propynal (HCCCHO) toward TMC-1 and in the laboratory to update line catalog available for transitions HCCCHO—specifically at frequencies lower than 30 GHz, which were previously discrepant a publicly catalog. The observed astronomical provided enough that, when combined with high-resolution (∼2 kHz) measurements taken laboratory, new, consistent fit both data was achieved. Now nearly exact (<1 frequency match J = 2–1 3–2 data,...
We use both chirped-pulse Fourier transform and frequency modulated absorption spectroscopy to study the rotational spectrum of 2-methoxyethanol in several regions ranging from 8.7-500 GHz. The resulting parameters permitted a search for this molecule Atacama Large Millimeter/submillimeter Array (ALMA) observations toward massive protocluster NGC 6334I as well source B low-mass protostellar system IRAS 16293-2422. 25 transitions are observed ALMA Band 4 data 6334I, first interstellar...
The determination of chemical mixture components is vital to a multitude scientific fields. Oftentimes spectroscopic methods are employed decipher the composition these mixtures. However, sheer density spectral features present in databases can make unambiguous assignment individual species challenging. Yet, commonly chemically related due environmental processes or shared precursor molecules. Therefore, analysis relevance molecule important when determining which mixture. In this paper, we...
The determination of chemical mixture components is vital to a multitude scientific fields. Oftentimes spectroscopic methods are employed decipher the composition these mixtures. However, sheer density spectral features present in databases can make unambiguous assignment individual species challenging. Yet, commonly chemically related due environmental processes or shared precursor molecules. Therefore, analysis relevance molecule important when determining which mixture. In this paper, we...
Polycyclic aromatic hydrocarbons (PAHs) are among the most ubiquitous compounds in universe, accounting for up to ~25% of all interstellar carbon. Since unsubstituted PAHs do not possess permanent dipole moments, they invisible radio astronomy. Constraining their abundances relies on detection polar chemical proxies, such as nitriles. We report 2- and 4-cyanopyrene, isomers recently detected 1-cyanopyrene. find that these present an abundance ratio ~2:1:2, which mirrors number equivalent...
We used new high spectral resolution observations of propynal (HCCCHO) towards TMC-1 and in the laboratory to update line catalog available for transitions HCCCHO - specifically at frequencies lower than 30 GHz which were previously discrepant a publicly catalog. The observed astronomical provided enough that, when combined with high-resolution (~2 kHz) measurements taken laboratory, new, consistent fit both data was achieved. Now nearly exact (<1 frequency match J=2-1 3-2 data, using Markov...
Polycyclic aromatic hydrocarbons (PAHs) are expected to be the most abundant class of organic molecules in space. Their interstellar lifecycle is not well understood, and progress hampered by difficulties detecting individual PAH molecules. Here, we present discovery CN-functionalized pyrene, a 4-ring PAH, dense cloud TMC-1 using 100-m Green Bank Telescope. We derive an abundance 1-cyanopyrene ~1.52 x $10^{12}$ cm$^{-2}$, from this estimate that un-substituted pyrene accounts for up...
We report the detection of lowest energy conformer $E$-1-cyano-1,3-butadiene ($E$-1-C$_4$H$_5$CN), a linear isomer pyridine, using fourth data reduction GOTHAM deep spectral survey toward TMC-1 with 100 m Green Bank Telescope. performed velocity stacking and matched filter analyses Markov chain Monte Carlo simulations find evidence for presence this molecule at 5.1$σ$ level. derive total column density $3.8^{+1.0}_{-0.9}\times 10^{10}$ cm$^{-2}$, which is predominantly found two four...