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Full-Text Articles in Physical Sciences and Mathematics
Conserved Vibrational Coherence In The Ultrafast Rearrangement Of 2-Nitrotoluene Radical Cation, Derrick Ampadu Boateng, Mi'kayla D. Word, Lavrenty Gutsev, Puru Jena, Katharine M. Tibbetts
Conserved Vibrational Coherence In The Ultrafast Rearrangement Of 2-Nitrotoluene Radical Cation, Derrick Ampadu Boateng, Mi'kayla D. Word, Lavrenty Gutsev, Puru Jena, Katharine M. Tibbetts
Chemistry Publications
2-Nitrotoluene (2-NT) is a good model for both photolabile protecting groups for organic synthesis and the military explosive 2,4,6-trinitrotoluene (TNT). In addition to the direct C−NO2 bond-cleavage reaction that initiates detonation in TNT, 2-NT undergoes an H atom attack reaction common to the photolabile 2-nitrobenzyl group, which forms the aci-nitro tautomer. In this work, femtosecond pump−probe measure- ments with mass spectrometric detection and density functional theory (DFT) calculations demonstrate that the initially prepared vibrational coherence in the 2-NT radical cation (2- NT+) is preserved following H atom attack. Strong-field adiabatic ionization is used to prepare 2-NT+, which can overcome a …
Probing Coherent Vibrations Of Organic Phosphonate Radical Cations With Femtosecond Time-Resolved Mass Spectrometry, Derrick Ampadu Boateng, Mi'kayla D. Word, Katharine M. Tibbetts
Probing Coherent Vibrations Of Organic Phosphonate Radical Cations With Femtosecond Time-Resolved Mass Spectrometry, Derrick Ampadu Boateng, Mi'kayla D. Word, Katharine M. Tibbetts
Chemistry Publications
Organic phosphates and phosphonates are present in a number of cellular components that can be damaged by exposure to ionizing radiation. This work reports femtosecond time-resolved mass spectrometry (FTRMS) studies of three organic phosphonate radical cations that model the DNA sugar-phosphate backbone: dimethyl methylphosphonate (DMMP), diethyl methylphosphonate (DEMP), and diisopropyl methylphosphonate (DIMP). Upon ionization, each molecular radical cation exhibits unique oscillatory dynamics in its ion yields resulting from coherent vibrational excitation. DMMP has particularly well-resolved 45 fs (732 ± 28 cm−1) oscillations with a weak feature at 610–650 cm−1, while DIMP exhibits bimodal oscillations with a period of ∼55 fs …
Coherent Vibrational And Dissociation Dynamics Of Polyatomic Radical Cations, Katharine M. Tibbetts
Coherent Vibrational And Dissociation Dynamics Of Polyatomic Radical Cations, Katharine M. Tibbetts
Chemistry Publications
The ultrafast dynamics of polyatomic radical cat- ions contribute to important processes including energy transfer in photovoltaics, electron transfer in photocataly- sis, radiation-induced DNA damage, and chemical reac- tions in the upper atmosphere and space. Probing these dynamics in the gas phase is challenging due to the rapid dissociation of polyatomic radical cations following elec- tron removal, which arises from excess electronic excita- tion of the molecule during the ionization process. This Concept article introduces the reader to how the pump- probe technique of femtosecond time-resolved mass spectrometry (FTRMS) can overcome this challenge to capture coherent vibrational dynamics on the …