Photo-control of bimolecular reactions: reactivity of the long-lived Rhodamine 6G triplet excited state with ˙NO

2021 ◽  
Author(s):  
Luke MacAleese ◽  
Bun Chan ◽  
Mathilde Bouakil ◽  
Philippe Dugourd ◽  
Richard A. J. O’Hair
Keyword(s):  
Excited State ◽  
Rhodamine 6G ◽  
Ion Trap ◽  
Triplet Excited State ◽  
Bimolecular Reactions ◽  
Mass Spectrometers ◽  
Chemical Mechanisms ◽  
Excited Species

Step-by-step photo-chemical mechanisms are becoming experimentally observable in extremely dilute environments as found in ion trap mass spectrometers where long lived excited species may react with controlled pressures of neutral reagents.

scholarly journals Quadrupole Ion Trap Mass Spectrometer for Ice Giant Atmospheres Exploration

2021 ◽  
Vol 217 (1) ◽  
Author(s):  
J. Simcic ◽  
D. Nikolić ◽  
A. Belousov ◽  
D. Atkinson ◽  
C. Lee ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Ion Trap ◽  
Quadrupole Ion Trap ◽  
Atomic Mass ◽  
Charge Ratio ◽  
Inlet System ◽  
Mass Spectrometers ◽  
Ion Trap Mass Spectrometer ◽  
Entry Probe ◽  
Composition Measurements

AbstractTo date, a variety of different types of mass spectrometers have been utilized on missions to study the composition of atmospheres of solar system bodies, including Venus, Mars, Jupiter, Titan, the moon, and several comets. With the increasing interest in future small probe missions, mass spectrometers need to become even more versatile, lightweight, compact, and sensitive.For in situ exploration of ice giant atmospheres, the highest priority composition measurements are helium and the other noble gases, noble gas isotopes, including 3He/4He, and other key isotopes like D/H. Other important but lower priority composition measurements include abundances of volatiles C, N, S, and P; isotopes 13C/12C, 15N/14N, 18O/17O/16O; and disequilibrium species PH3, CO, AsH3, GeH4, and SiH4. Required measurement accuracies are largely defined by the accuracies achieved by the Galileo (Jupiter) probe Neutral Mass Spectrometer and Helium Abundance Detectors, and current measurement accuracies of solar abundances.An inherent challenge of planetary entry probe mass spectrometers is the introduction of material to be sampled (gas, solid, or liquid) into the instrument interior, which operates at a vacuum level. Atmospheric entry probe mass spectrometers typically require a specially designed sample inlet system, which ideally provides highly choked, nearly constant mass-flow intake over a large range of ambient pressures. An ice giant descent probe would have to operate for 1-2 hours over a range of atmospheric pressures, possibly covering 2 or more orders of magnitude, from the tropopause near 100 mbar to at least 10 bars, in an atmospheric layer of depth beneath the tropopause of about 120 km at Neptune and about 150 km at Uranus.The Jet Propulsion Laboratory’s Quadrupole Ion Trap Mass Spectrometer (QITMS) is being developed to achieve all of these requirements. A compact, wireless instrument with a mass of only 7.5 kg, and a volume of 7 liters (7U), the JPL QITMS is currently the smallest flight mass spectrometer available for possible use on planetary descent probes as well as small bodies, including comet landers and surface sample return missions. The QITMS is capable of making measurements of all required constituents in the mass range of 1–600 atomic mass units (u) at a typical speed of 50 mass spectra per second, with a sensitivity of up to $10^{13}$ 10 13  counts/mbar/sec and mass resolution of $m/\Delta m=18000$ m / Δ m = 18000 at m/q = 40. (Throughout this paper we use the unit of m/q = u/e for the mass-to-charge ratio, where atomic mass unit and elementary charge are $1~\text{u} = 1.66\times 10^{-27}~\text{kg}$ 1 u = 1.66 × 10 − 27 kg and $1\text{e} = 1.6\times 10^{-19}$ 1 e = 1.6 × 10 − 19 C, respectively.) The QITMS features a novel MEMS-based inlet system driven by a piezoelectric actuator that continuously regulates gas flow at inlet pressures of up to 100 bar.In this paper, we present an overview of the QITMS capabilities, including instrument design and characteristics of the inlet system, as well as the most recent results from laboratory measurements in different modes of operation, especially suitable for ice giant atmospheres exploration.

scholarly journals Ultra long‐lived triplet excited state in water at room temperature: Insights on the molecular design of tridecafullerenes

2021 ◽  
Author(s):  
Javier Ramos-Soriano ◽  
Alfonso Pérez-Sánchez ◽  
Sergio Ramírez-Barroso ◽  
Beatriz M. Illescas ◽  
Khalid Azmani ◽  
...  
Keyword(s):  
Excited State ◽  
Room Temperature ◽  
Molecular Design ◽  
Triplet Excited State

scholarly journals Triplet energies and excimer formation in meta - and para -linked carbazolebiphenyl matrix materials

2015 ◽  
Vol 373 (2044) ◽  
pp. 20140446 ◽  
Author(s):  
Sergey A. Bagnich ◽  
Alexander Rudnick ◽  
Pamela Schroegel ◽  
Peter Strohriegl ◽  
Anna Köhler
Keyword(s):  
Excited State ◽  
Triplet State ◽  
Spectroscopic Investigation ◽  
Triplet Excited State ◽  
Conjugation Length ◽  
Triplet Energy ◽  
Excimer Formation

We present a spectroscopic investigation on the effect of changing the position where carbazole is attached to biphenyl in carbazolebiphenyl (CBP) on the triplet state energies and the propensity to excimer formation. For this, two CBP derivatives have been prepared with the carbazole moieties attached at the ( para ) 4- and 4 ′ -positions ( p CBP) and at the ( meta ) 3- and 3 ′ -positions ( m CBP) of the biphenyls. These compounds are compared to analogous m CDBP and p CDBP, i.e. two highly twisted carbazoledimethylbiphenyls, which have a high triplet energy at about 3.0 eV and tend to form triplet excimers in a neat film. This torsion in the structure is associated with localization of the excited state onto the carbazole moieties. We find that in m CBP and p CBP, excimer formation is prevented by localization of the triplet excited state onto the central moiety. As conjugation can continue from the central biphenyls into the nitrogen of the carbazole in the para -connected p CBP, emission involves mainly the benzidine. By contrast, the meta -linkage in m CBP limits conjugation to the central biphenyl. The associated shorter conjugation length is the reason for the higher triplet energy of 2.8 eV in m CBP compared with the 2.65 eV in p CBP.

Investigation of the triplet excited state and application of cationic meso-tetra(cisplatin)porphyrins in antimicrobial photodynamic therapy

2021 ◽  
pp. 102459
Author(s):  
Dariane Clerici Jornada ◽  
Rafael de Queiroz Garcia ◽  
Carolina Hahn da Silveira ◽  
Lino Misoguti ◽  
Cleber Renato Mendonça ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Excited State ◽  
Antimicrobial Photodynamic Therapy ◽  
Triplet Excited State

scholarly journals Electron Transfer Initiated Reactions Photoinduced by Pterins

Pteridines ◽  
2011 ◽  
Vol 22 (1) ◽  
pp. 111-119 ◽  
Author(s):  
Carolina Lorente ◽  
Gabriela Petroselli ◽  
M. Laura Dántola ◽  
Esther Oliveros ◽  
Andrés H. Thomas
Keyword(s):  
Electron Transfer ◽  
Excited State ◽  
Redox Reactions ◽  
Type I ◽  
Biological Processes ◽  
Type Ii ◽  
Triplet Excited State ◽  
Oxygen Production ◽  
Production Type ◽  
Transfer Mechanisms

Abstract Interest in the photochemistry and photophysics of pterins has increased since the participation of this family of compounds in different photobiological processes has been suggested or demonstrated in recent decades. Pterins participate in relevant biological processes, such as metabolic redox reactions, and can photoinduce the oxidation of biomolecules through both electron transfer mechanisms (Type I) and singlet oxygen production (Type II). This article describes recent findings on electron transfer-initiated reactions photoinduced by the triplet excited state of pterins and connects them in the context of photosensitized processes of biological relevance.

scholarly journals Singlet and Triplet Excited-State Dynamics Study of the Keto and Enol Tautomers of Cytosine

ChemPhysChem ◽  
2013 ◽  
Vol 14 (13) ◽  
pp. 2920-2931 ◽  
Author(s):  
Sebastian Mai ◽  
Philipp Marquetand ◽  
Martin Richter ◽  
Jesús González-Vázquez ◽  
Leticia González
Keyword(s):  
Excited State ◽  
Triplet Excited State ◽  
Excited State Dynamics

Triplet Excited State Behavior of Naphthalene-Based Pseudopeptides in the Presence of Energy Donors

2012 ◽  
Vol 116 (33) ◽  
pp. 9957-9962 ◽  
Author(s):  
Paula Bonancía ◽  
Laura Vigara ◽  
Francisco Galindo ◽  
Santiago V. Luis ◽  
M. Consuelo Jiménez ◽  
...  
Keyword(s):  
Excited State ◽  
Triplet Excited State ◽  
State Behavior
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