Formation of highly excited iodine atoms from multiphoton excitation of CH3I

Kristján Matthíasson; Greta Koumarianou; Meng Xu Jiang; Pavle Glodic; Peter C. Samartzis; Ágúst Kvaran

doi:10.1039/c9cp06242d

Formation of highly excited iodine atoms from multiphoton excitation of CH₃I

Kristján Matthíasson, Greta Koumarianou, Meng Xu Jiang, Pavle Glodic, Peter C. Samartzis, Ágúst Kvaran

Research output: Contribution to journal › Article › peer-review

2 Citations (Scopus)

Abstract

Mass resolved REMPI spectra, as well as CH₃⁺and I⁺ ion and photoelectron images, were recorded for two-photon resonant excitations of CH₃I via s, p and d Rydberg states (CH₃I∗∗) in the excitation region of 55 700 to 70 000 cm^-1. Photoelectron (PE) and ion kinetic energy release spectra (KERs) were derived from the images. The data revealed that after the two-photon resonant excitation, an additional photon is absorbed to form one or more superexcited state(s) (CH₃I^#), followed by branching into three pathways. The major one is the dissociation of CH₃I^# to form excited Rydberg states of iodine atoms (I∗∗) along with CH₃(X), a phenomenon not commonly observed in methyl halides. The second (minor) pathway involves autoionization of CH₃I^# towards CH₃I⁺(X), which absorbs another photon to form CH₃⁺ along with I/I∗ and the third one (minor) is CH₃I^# dissociation towards the ion pair, CH₃⁺ + I^-, prior to I^- electron ejection. Furthermore, one-photon non-resonant dissociation of CH₃I to form CH₃(X) and I/I∗ prior to three-photon ionization of the fragments is also detected.

Original language	English
Pages (from-to)	4984-4992
Number of pages	9
Journal	Physical Chemistry Chemical Physics
Volume	22
Issue number	9
DOIs	https://doi.org/10.1039/c9cp06242d
Publication status	Published - 7 Mar 2020

Bibliographical note

Funding Information:
The financial support of the University Research Fund, University of Iceland and the Icelandic Research Fund (Grant No. 184693-051) is gratefully acknowledged. The imaging part of the reported results was carried out at the Ultraviolet Laser Facility at IESL-FORTH, supported in part by the European Union’s Horizon 2020 research and innovation programme LASERLAB-EUROPE (Grant Agreement No. 654148) and in part by HELLAS-CH (MIS 5002735) implemented under ‘‘Action for Strengthening Research and Innovation Infrastructures,’’ funded by the Operational Programme ‘‘Competitiveness, Entrepreneurship and Innovation’’ (NSRF 2014– 2020) and co-financed by Greece and the European Union (European Regional Development Fund).

Publisher Copyright:
© 2020 the Owner Societies.

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10.1039/c9cp06242d

Cite this

@article{76fdc88231e14b95be433c132afad330,

title = "Formation of highly excited iodine atoms from multiphoton excitation of CH3I",

abstract = "Mass resolved REMPI spectra, as well as CH3+and I+ ion and photoelectron images, were recorded for two-photon resonant excitations of CH3I via s, p and d Rydberg states (CH3I∗∗) in the excitation region of 55 700 to 70 000 cm-1. Photoelectron (PE) and ion kinetic energy release spectra (KERs) were derived from the images. The data revealed that after the two-photon resonant excitation, an additional photon is absorbed to form one or more superexcited state(s) (CH3I#), followed by branching into three pathways. The major one is the dissociation of CH3I# to form excited Rydberg states of iodine atoms (I∗∗) along with CH3(X), a phenomenon not commonly observed in methyl halides. The second (minor) pathway involves autoionization of CH3I# towards CH3I+(X), which absorbs another photon to form CH3+ along with I/I∗ and the third one (minor) is CH3I# dissociation towards the ion pair, CH3+ + I-, prior to I- electron ejection. Furthermore, one-photon non-resonant dissociation of CH3I to form CH3(X) and I/I∗ prior to three-photon ionization of the fragments is also detected.",

author = "Kristj{\'a}n Matth{\'i}asson and Greta Koumarianou and Jiang, {Meng Xu} and Pavle Glodic and Samartzis, {Peter C.} and {\'A}g{\'u}st Kvaran",

note = "Funding Information: The financial support of the University Research Fund, University of Iceland and the Icelandic Research Fund (Grant No. 184693-051) is gratefully acknowledged. The imaging part of the reported results was carried out at the Ultraviolet Laser Facility at IESL-FORTH, supported in part by the European Union{\textquoteright}s Horizon 2020 research and innovation programme LASERLAB-EUROPE (Grant Agreement No. 654148) and in part by HELLAS-CH (MIS 5002735) implemented under {\textquoteleft}{\textquoteleft}Action for Strengthening Research and Innovation Infrastructures,{\textquoteright}{\textquoteright} funded by the Operational Programme {\textquoteleft}{\textquoteleft}Competitiveness, Entrepreneurship and Innovation{\textquoteright}{\textquoteright} (NSRF 2014– 2020) and co-financed by Greece and the European Union (European Regional Development Fund). Publisher Copyright: {\textcopyright} 2020 the Owner Societies.",

year = "2020",

month = mar,

day = "7",

doi = "10.1039/c9cp06242d",

language = "English",

volume = "22",

pages = "4984--4992",

journal = "Physical Chemistry Chemical Physics",

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T1 - Formation of highly excited iodine atoms from multiphoton excitation of CH3I

AU - Matthíasson, Kristján

AU - Koumarianou, Greta

AU - Jiang, Meng Xu

AU - Glodic, Pavle

AU - Samartzis, Peter C.

AU - Kvaran, Ágúst

N1 - Funding Information: The financial support of the University Research Fund, University of Iceland and the Icelandic Research Fund (Grant No. 184693-051) is gratefully acknowledged. The imaging part of the reported results was carried out at the Ultraviolet Laser Facility at IESL-FORTH, supported in part by the European Union’s Horizon 2020 research and innovation programme LASERLAB-EUROPE (Grant Agreement No. 654148) and in part by HELLAS-CH (MIS 5002735) implemented under ‘‘Action for Strengthening Research and Innovation Infrastructures,’’ funded by the Operational Programme ‘‘Competitiveness, Entrepreneurship and Innovation’’ (NSRF 2014– 2020) and co-financed by Greece and the European Union (European Regional Development Fund). Publisher Copyright: © 2020 the Owner Societies.

PY - 2020/3/7

Y1 - 2020/3/7

N2 - Mass resolved REMPI spectra, as well as CH3+and I+ ion and photoelectron images, were recorded for two-photon resonant excitations of CH3I via s, p and d Rydberg states (CH3I∗∗) in the excitation region of 55 700 to 70 000 cm-1. Photoelectron (PE) and ion kinetic energy release spectra (KERs) were derived from the images. The data revealed that after the two-photon resonant excitation, an additional photon is absorbed to form one or more superexcited state(s) (CH3I#), followed by branching into three pathways. The major one is the dissociation of CH3I# to form excited Rydberg states of iodine atoms (I∗∗) along with CH3(X), a phenomenon not commonly observed in methyl halides. The second (minor) pathway involves autoionization of CH3I# towards CH3I+(X), which absorbs another photon to form CH3+ along with I/I∗ and the third one (minor) is CH3I# dissociation towards the ion pair, CH3+ + I-, prior to I- electron ejection. Furthermore, one-photon non-resonant dissociation of CH3I to form CH3(X) and I/I∗ prior to three-photon ionization of the fragments is also detected.

AB - Mass resolved REMPI spectra, as well as CH3+and I+ ion and photoelectron images, were recorded for two-photon resonant excitations of CH3I via s, p and d Rydberg states (CH3I∗∗) in the excitation region of 55 700 to 70 000 cm-1. Photoelectron (PE) and ion kinetic energy release spectra (KERs) were derived from the images. The data revealed that after the two-photon resonant excitation, an additional photon is absorbed to form one or more superexcited state(s) (CH3I#), followed by branching into three pathways. The major one is the dissociation of CH3I# to form excited Rydberg states of iodine atoms (I∗∗) along with CH3(X), a phenomenon not commonly observed in methyl halides. The second (minor) pathway involves autoionization of CH3I# towards CH3I+(X), which absorbs another photon to form CH3+ along with I/I∗ and the third one (minor) is CH3I# dissociation towards the ion pair, CH3+ + I-, prior to I- electron ejection. Furthermore, one-photon non-resonant dissociation of CH3I to form CH3(X) and I/I∗ prior to three-photon ionization of the fragments is also detected.

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