Article
Chemistry, Physical
Pedro Recio, Javier Cachon, Luis Rubio-Lago, David Chicharro, Alexandre Zanchet, Paulo Limao-Vieira, Nelson de Oliveira, Peter C. Samartzis, Sonia Marggi Poullain, Luis Banares
Summary: The photodissociation dynamics and photofragment alignment of bromoiodomethane were studied at 193 nm using both experimental and theoretical methods. The results showed that prompt C-X cleavage competes with fast internal conversion and stochastic dissociation, and the obtained theoretical results provide a complete picture of the photodissociation dynamics.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Physical
Pedro Recio, Javier Cachon, Luis Rubio-Lago, David Chicharro, Alexandre Zanchet, Paulo Limao-Vieira, Nelson de Oliveira, Peter C. Samartzis, Sonia Marggi Poullain, Luis Banares
Summary: The photodissociation dynamics and photofragment alignment of bromoiodomethane were studied through experimental and theoretical approaches. The results showed that prompt C-X cleavage competed with fast internal conversion and stochastic dissociation in lower electronic states at an excitation wavelength of 193 nm. The C-Br bond breakage mainly occurs in the 13A ' electronic state through a predissociation pathway.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Physical
Isaac A. Ramphal, Mark Shapero, Daniel M. Neumark
Summary: The photodissociation of jet-cooled cyclohexyl was studied by exciting the radicals to their 3p Rydberg state by using 248 nm laser light and detecting photoproducts by photofragment translational spectroscopy. Both H atom loss and dissociation to heavy fragment pairs are observed. The study found a two-component translational energy distribution for the H atom loss channel, with fast component attributed to impulsive cleavage directly from an excited state and slow component due to statistical decomposition of hot cyclohexyl radicals.
JOURNAL OF PHYSICAL CHEMISTRY A
(2021)
Article
Chemistry, Organic
Seoyeon Kim, Yunjeong Lee, Eun Jin Cho
Summary: In this study, a visible-light-induced selective homocoupling reaction of propargyl bromides to form 1,5-diynes was developed. The key step in the reaction involves the generation of propargyl radicals through a reductive quenching cycle of the photoexcited [Ir(III)]* photocatalyst. The formed 1,5-diyne can be further converted to functionalized indole derivatives through coupling reactions.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Run R. Li, Mark R. Hoffmann
Summary: In this study, the low-lying electronic energy levels of the propargyl radical were calculated using the MRCISD(TQ) method, revealing that the strong absorption is attributed to a Franck-Condon-allowed electronic transition. Insights into the behavior of the multireference perturbative theory methods, GVVPT2 and GVVPT3, on a challenging system were also obtained.
JOURNAL OF PHYSICAL CHEMISTRY A
(2021)
Article
Chemistry, Multidisciplinary
Feng-Hua Zhang, Xiaochong Guo, Xianrong Zeng, Zhaobin Wang
Summary: In this study, a Cr-catalyzed enantioconvergent allenylation method was described to rapidly obtain chiral alpha-allenols with adjacent axial and central chiralities by reacting with racemic propargyl halides. This method exhibited excellent selectivity control and broad substrate scope, and facilitated access to all four stereoisomers when combined with other reactions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Organic
Chang-Qing Liu, Hang Li, Bo Wang, Zi-Yi Guo, Yu Wang, Ji-Tan Zhang, Mei-Hua Xie
Summary: A switchable di- and monosulfonylation reaction of propargyl alcohols with sodium sulfinates has been developed, leading to the successful synthesis of (E)-allyl, vinyldisulfones, and propargyl sulfones with good to excellent yields. This protocol has the advantages of using readily available starting materials, a broad substrate scope, and can be conducted in an air-atmosphere and under metal-free conditions.
ORGANIC CHEMISTRY FRONTIERS
(2022)
Review
Chemistry, Organic
Marcus Muresan, Hariharaputhiran Subramanian, Mukund P. Sibi, James R. Green
Summary: This minireview discusses the increasing importance of propargyl radicals as synthetic intermediates in recent years. It covers the mechanisms of their generation and reactions, as well as their applications in the synthesis of target molecules.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2021)
Article
Chemistry, Organic
Man Zhang, Sixin Wu, Lei Wang, Ziqin Xia, Kaimo Kuang, Qiankun Xu, Fangli Zhao, Nengneng Zhou
Summary: A visible-light-induced radical cascade acylation/cyclization/aromatization reaction was developed for the construction of 3-acylated quinolines from N-propargyl aromatic amines and acyl oxime esters. This approach utilizes acyl oxime esters as precursors of acyl radicals and acylation reagents, Eosin Y as the photocatalyst, and acetonitrile as the solvent, providing a convenient route for the synthesis of 3-acylated quinolines via the C-C bond cleavage of acyl oxime esters.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Physical
Johanna E. E. Rinaman, Craig Murray
Summary: The photolysis of acetylacetone (AcAc) was studied using velocity-map ion imaging with pulsed nanosecond lasers. The results showed that the dissociation of AcAc occurs with lifetimes longer than the laser pulse duration but shorter than the molecular rotation timescale. It was also found that the excitation of AcAc in the strong UV absorption band leads to the formation of neutral product pairs, possibly via a Norrishtype I mechanism.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Physical
Balaganesh Muthiah, Toshio Kasai, King-Chuen Lin
Summary: This study investigated the photodissociation of di- and tri-halogenated methanes including CH2BrCl and CHBr2Cl at 248 nm using CRDS. The quantum yields and spectra of Br-2 and BrCl fragments were determined, and ab initio theoretical methods were employed to evaluate the potential energy surface for their dissociation pathways. The experimental results showed that only Br-2 fragments were produced in the photolysis of CHBr2Cl.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Optics
Amandine Baillard, Pavel Loiko, Daniel Rytz, Sebastian Schwung, Michael Fromager, Alain Braud, Patrice Camy
Summary: This article reports the first laser operation of a Sm3+-doped monoclinic KGd(WO4)2 double tungstate crystal. The laser, pumped by a frequency-doubled optically pumped semiconductor laser, achieved high output power, slope efficiency, and linear polarization. The polarized spectroscopic properties of Sm3+ ions were also determined.
Article
Optics
Pavel Loiko, Daniel Rytz, Sebastian Schwung, Patrick Pues, Thomas Justel, Jean-Louis Doualan, Patrice Camy
Summary: This study presents a watt-level highly efficient europium laser based on the stoichiometric KEu(WO4)(2) crystal, operating under green laser pumping. The laser achieved a peak output power at around 703 nm with a low laser threshold, demonstrating true continuous-wave operation.
Article
Chemistry, Physical
Dennis Milesevic, Divya Popat, Patrick Robertson, Claire Vallance
Summary: This study investigates the photodissociation dynamics of N,N-Dimethylformamide using velocity-map imaging. It reveals that excitation at different wavelengths leads to the cleavage of different bonds and the formation of various products, which are influenced by molecular geometries.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Muthiah Balaganesh, Joseph Song, Toshio Kasai, King-Chuen Lin
Summary: The photodissociation of 2,3-DBPC at 248 nm was studied to investigate Br-2 as the primary molecular product, with rotational spectra analysis confirming its origin. The vibrational ratio and quantum yield of Br-2 were determined experimentally, along with unimolecular rate constant for Br-2 elimination. The dissociation pathways and potential energy surfaces of 2,3-DBPC were also calculated using density functional theory and transition state barriers were determined.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Rico Mayro P. Tanyag, Camila Bacellar, Weiwu Pang, Charles Bernando, Luis F. Gomez, Curtis F. Jones, Ken R. Ferguson, Justin Kwok, Denis Anielski, Ali Belkacem, Rebecca Boll, John Bozek, Sebastian Carron, Gang Chen, Tjark Delmas, Lars Englert, Sascha W. Epp, Benjamin Erk, Lutz Foucar, Robert Hartmann, Alexander Hexemer, Martin Huth, Stephen R. Leone, Jonathan H. Ma, Stefano Marchesini, Daniel M. Neumark, Billy K. Poon, James Prell, Daniel Rolles, Benedikt Rudek, Artem Rudenko, Martin Seifrid, Michele Swiggers, Joachim Ullrich, Fabian Weise, Petrus Zwart, Christoph Bostedt, Oliver Gessner, Andrey F. Vilesov
Summary: Advancements in x-ray free-electron lasers have enabled single-shot imaging of fragile nanostructures, such as superfluid helium droplets, providing unique access to their sizes and shapes. This study reports on the size distributions of both pure and doped droplets collected from single-shot x-ray imaging, showing exponential size distribution and smaller average sizes for the doped droplets.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Optics
Yuki Kobayashi, Daniel M. Neumark, Stephen R. Leone
Summary: The theoretical investigation explores the role of complex dipole phase in attosecond charge migration probing. Using the iodobromoacetylene ion as an example, the study reveals that site-specific information of charge migration is encoded in the complex phase of cross dipole products. The simulation of transient absorption spectra successfully reconstructs the charge-migration dynamics.
Article
Chemistry, Multidisciplinary
Mark C. Babin, Martin DeWitt, Jascha A. Lau, Marissa L. Weichman, Jongjin B. Kim, Hongwei Song, Hua Guo, Daniel M. Neumark
Summary: The transition state of a chemical reaction, which serves as a dividing surface between reactants and products on the reaction potential energy surface (PES), is of fundamental interest in understanding chemical reactivity. However, its transient nature poses challenges for experimental characterization. In this study, a combination of negative-ion photodetachment-based transition-state spectroscopy and reduced-dimensionality quantum dynamical simulations is used to investigate the F + NH3 → HF + NH2 reaction, revealing detailed vibrational structure associated with the transition state. The study identifies vibrational Feshbach resonances in the product well of the F + NH3 PES and provides insights into the impact of resonances localized across the transition state and reactant complex on the bimolecular reaction dynamics.
Correction
Chemistry, Multidisciplinary
Zachary N. Heim, Daniel M. Neumark
ACCOUNTS OF CHEMICAL RESEARCH
(2023)
Article
Chemistry, Physical
Daniel M. Neumark
Summary: Cryo-SEVI is a high-resolution variant of anion photoelectron spectroscopy that has been successfully applied to the study of radicals, clusters, and transition states. It retains the versatility of conventional anion photoelectron spectroscopy while offering sub-meV resolution to resolve vibrational structure. Recent experiments in our laboratory using cryo-SEVI, including pre-excitation of anions with an infrared laser pulse, are described in this Feature Article.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Physical
Jascha A. Lau, Martin DeWitt, Mark A. Boyer, Mark C. Babin, Tonia Solomis, Max Grellmann, Knut R. Asmis, Anne B. McCoy, Daniel M. Neumark
Summary: High-resolution photoelectron spectra of vibrationally pre-excited vinoxide anions are obtained using the IR-cryo-SEVI technique. The method combines with vibrational perturbation theory to identify anharmonic couplings among vibrational states. The spectra reveal information about the anion and neutral states, including the splitting of the v3 fundamental mode and the estimation of the v5 fundamental frequency.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Multidisciplinary Sciences
Enrico Ridente, Diptarka Hait, Eric A. Haugen, Andrew D. Ross, Daniel M. Neumark, Martin Head-Gordon, Stephen R. Leone
Summary: Understanding the relaxation pathways of photoexcited molecules is crucial for gaining atomistic-level insight into photochemistry. In this study, the geometric relaxation (Jahn-Teller distortion) of the methane cation was investigated using time-resolved attosecond transient absorption spectroscopy. The results revealed that the distortion occurred within a few femtoseconds after strong-field ionization of methane. Coherent oscillations in the vibrational mode of the symmetry-broken cation were activated and detected in the x-ray signal, but damped within a few tens of femtoseconds. This study provides a comprehensive understanding of the molecular relaxation dynamics and has implications for studying complex systems.
Article
Chemistry, Physical
Benjamin W. W. Toulson, Diptarka Hait, Davide Facciala, Daniel M. M. Neumark, Stephen R. R. Leone, Martin Head-Gordon, Oliver Gessner
Summary: The UV photochemistry of small heteroaromatic molecules was studied in this research, which provides insights into fundamental photo-induced chemical transformations in moderately complex compounds. The study focused on the dynamics of 2-iodothiophene (C4H3IS) under 268 nm UV light-induced excitation. Experimental observations and theoretical calculations were combined to understand the relaxation dynamics and dissociation pathway of the molecule. The results showed a pi -> pi* excitation leading to iodine dissociation, followed by fragmentation in a specific bond-length region.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Walt Yang, Chin Lee, Steven Saric, Marvin N. N. Pohl, Daniel M. M. Neumark
Summary: The evaporation and scattering of Ne, CD4, and D2O from a dodecane flat liquid jet are studied. Translational energy distributions as a function of scattering angle are obtained using a rotatable mass spectrometer. The evaporation experiments reveal a Maxwell-Boltzmann distribution with a cosine angular distribution superimposed on a weak isotropic background. The scattering experiments show contributions from impulsive scattering and thermal desorption. At select incident angles for the three systems, the angular distributions show super-specular scattering for the impulsive scattering channel, attributed to anisotropic momentum transfer to the liquid surface. The impulsive scattering channel is analyzed with a soft-sphere model to explore energy transfer between the scatterer and liquid as a function of deflection angle. Compared to Ne scattering, the polyatomic gases exhibit more thermal desorption and a higher degree of internal excitation in the impulsive scattering channel.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Optics
Nicolette G. Puskar, Yen-Cheng Lin, James D. Gaynor, Maximilian C. Schuchter, Siddhartha Chattopadhyay, Carlos Marante, Ashley P. Fidler, Clare L. Keenan, Luca Argenti, Daniel M. Neumark, Stephen R. Leone
Summary: Attosecond noncollinear four-wave-mixing spectroscopy was used to measure the autoionization decay lifetimes of inner valence electronic excitations in neon atoms. The results show that the lifetimes of 3s, 3p, and 3d states are 7 +/- 2 fs, 48 +/- 8 fs, and 427 +/- 40 fs, respectively. Theoretical calculations verify the experimental findings and provide an assessment of the electron correlation in the autoionization process.
Article
Optics
James D. Gaynor, Ashley P. Fidler, Yuki Kobayashi, Yen-Cheng Lin, Clare L. Keenan, Daniel M. Neumark, Stephen R. Leone
Summary: Attosecond four-wave mixing (FWM) spectroscopy is used to study the Rydberg wave packet dynamics in argon atoms. The experiment shows that the emitted signals from individual Rydberg states have oscillatory structure and persist beyond the expected lifetimes. The coherent amplitude transfer is driven by nonresonant NIR light through dark states during the FWM process.
Article
Optics
Ashley P. Fidler, Yen-Cheng Lin, James D. Gaynor, C. William McCurdy, Stephen R. Leone, Robert R. Lucchese, Daniel M. Neumark
Summary: This study investigates the dynamics of excited Rydberg states of CO2 molecule using attosecond extreme ultraviolet (XUV) four-wave mixing (FWM) spectroscopy, and observes emission signals from specific Rydberg series with consistent lifetimes. The calculated oscillator strengths confirm that the nonlinear spectra are dominated by specific excitation and emission pathways. The results demonstrate that nonlinear spectroscopic techniques are versatile tools for measuring ultrafast dynamics in polyatomic systems and accessing difficult-to-probe dynamics.
Correction
Chemistry, Multidisciplinary
Andrew D. Ross, Diptarka Hait, Valeriu Scutelnic, Eric A. Haugen, Enrico Ridente, Mikias B. Balkew, Daniel M. Neumark, Martin Head-Gordon, Stephen R. Leone
Article
Chemistry, Multidisciplinary
Andrew D. Ross, Diptarka Hait, Valeriu Scutelnic, Eric A. Haugen, Enrico Ridente, Mikias B. Balkew, Daniel M. Neumark, Martin Head-Gordon, Stephen R. Leone
Summary: X-ray Transient Absorption Spectroscopy (XTAS) and theoretical calculations were used to investigate the ionization process of CCl4+. The results revealed symmetry breaking and the formation of the Cl-CCl+(3) complex after ionization, providing important insights into new species during the dissociation of CCl4+.
Article
Chemistry, Physical
Mark C. Babin, Martin DeWitt, Jascha A. Lau, Marissa L. Weichman, Jongjin B. Kim, Lan Cheng, Daniel M. Neumark
Summary: High-resolution anion photoelectron spectra of cryogenically cooled NiO2- anions are obtained using slow photoelectron velocity-map imaging (cryo-SEVI). The experimental spectra reveal previously unobserved vibrational structure in all three electronic bands and are consistent with previous measurements and calculations.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)