Photoelectron-Photofragment Coincidence Spectroscopy With Ions Prepared in a Cryogenic Octopole Accumulation Trap: Collisional Excitation and Buffer Gas Cooling

A cryogenic octopole accumulation trap (COAT) has been coupled to a photoelectron-photofragment coincidence (PPC) spectrometer allowing for improved control over anion vibrational excitation. The anions are heated and cooled via collisions with buffer gas <17 K. Shorter trapping times (500 μs...

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Main Authors: Ben B. Shen, Katharine G. Lunny, Yanice Benitez, Robert E. Continetti
Format: Article
Language:English
Published: Frontiers Media S.A. 2019-04-01
Series:Frontiers in Chemistry
Subjects:
Online Access:https://www.frontiersin.org/article/10.3389/fchem.2019.00295/full
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author Ben B. Shen
Katharine G. Lunny
Yanice Benitez
Robert E. Continetti
author_facet Ben B. Shen
Katharine G. Lunny
Yanice Benitez
Robert E. Continetti
author_sort Ben B. Shen
collection DOAJ
description A cryogenic octopole accumulation trap (COAT) has been coupled to a photoelectron-photofragment coincidence (PPC) spectrometer allowing for improved control over anion vibrational excitation. The anions are heated and cooled via collisions with buffer gas <17 K. Shorter trapping times (500 μs) prevent thermalization and result in anions with high internal excitation while longer trapping times (80 ms) at cryogenic temperatures thermalize the ions to the temperature of the buffer gas. The capabilities of the COAT are demonstrated using PPC spectroscopy of O3- at 388 nm (Ehν = 3.20 eV). Cooling the precursor anions with COAT resulted in the elimination of the autodetachment of vibrationally excited O2- produced by the photodissociation O3- + hν → O + O2-(v ≥ 4). Under heating conditions, a lower limit temperature for the anions was determined to be 1,500 K through Franck-Condon simulations of the photodetachment spectrum of O3-, considering a significant fraction of the ions undergo photodissociation in competition with photodetachment. The ability to cool or heat ions by varying ion injection and trapping duration in COAT provides a new flexibility for studying the spectroscopy of cold ions as well as thermally activated processes.
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spelling doaj.art-36cdb381bf574f17a1e6eab17669f1212022-12-21T19:47:59ZengFrontiers Media S.A.Frontiers in Chemistry2296-26462019-04-01710.3389/fchem.2019.00295454857Photoelectron-Photofragment Coincidence Spectroscopy With Ions Prepared in a Cryogenic Octopole Accumulation Trap: Collisional Excitation and Buffer Gas CoolingBen B. ShenKatharine G. LunnyYanice BenitezRobert E. ContinettiA cryogenic octopole accumulation trap (COAT) has been coupled to a photoelectron-photofragment coincidence (PPC) spectrometer allowing for improved control over anion vibrational excitation. The anions are heated and cooled via collisions with buffer gas <17 K. Shorter trapping times (500 μs) prevent thermalization and result in anions with high internal excitation while longer trapping times (80 ms) at cryogenic temperatures thermalize the ions to the temperature of the buffer gas. The capabilities of the COAT are demonstrated using PPC spectroscopy of O3- at 388 nm (Ehν = 3.20 eV). Cooling the precursor anions with COAT resulted in the elimination of the autodetachment of vibrationally excited O2- produced by the photodissociation O3- + hν → O + O2-(v ≥ 4). Under heating conditions, a lower limit temperature for the anions was determined to be 1,500 K through Franck-Condon simulations of the photodetachment spectrum of O3-, considering a significant fraction of the ions undergo photodissociation in competition with photodetachment. The ability to cool or heat ions by varying ion injection and trapping duration in COAT provides a new flexibility for studying the spectroscopy of cold ions as well as thermally activated processes.https://www.frontiersin.org/article/10.3389/fchem.2019.00295/fullion trapozonidephotoelectronphotofragmentcoincidence spectroscopycollisional excitation
spellingShingle Ben B. Shen
Katharine G. Lunny
Yanice Benitez
Robert E. Continetti
Photoelectron-Photofragment Coincidence Spectroscopy With Ions Prepared in a Cryogenic Octopole Accumulation Trap: Collisional Excitation and Buffer Gas Cooling
Frontiers in Chemistry
ion trap
ozonide
photoelectron
photofragment
coincidence spectroscopy
collisional excitation
title Photoelectron-Photofragment Coincidence Spectroscopy With Ions Prepared in a Cryogenic Octopole Accumulation Trap: Collisional Excitation and Buffer Gas Cooling
title_full Photoelectron-Photofragment Coincidence Spectroscopy With Ions Prepared in a Cryogenic Octopole Accumulation Trap: Collisional Excitation and Buffer Gas Cooling
title_fullStr Photoelectron-Photofragment Coincidence Spectroscopy With Ions Prepared in a Cryogenic Octopole Accumulation Trap: Collisional Excitation and Buffer Gas Cooling
title_full_unstemmed Photoelectron-Photofragment Coincidence Spectroscopy With Ions Prepared in a Cryogenic Octopole Accumulation Trap: Collisional Excitation and Buffer Gas Cooling
title_short Photoelectron-Photofragment Coincidence Spectroscopy With Ions Prepared in a Cryogenic Octopole Accumulation Trap: Collisional Excitation and Buffer Gas Cooling
title_sort photoelectron photofragment coincidence spectroscopy with ions prepared in a cryogenic octopole accumulation trap collisional excitation and buffer gas cooling
topic ion trap
ozonide
photoelectron
photofragment
coincidence spectroscopy
collisional excitation
url https://www.frontiersin.org/article/10.3389/fchem.2019.00295/full
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