Ultrafast reaction dynamics of electronically excited [ital [tilde A]] state of ammonia clusters

Journal Article · Thu Jul 01 04:00:00 EDT 1993 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.465752· OSTI ID:6487305

Wei, S; Purnell, J; Buzza, S A; Castleman, Jr, A W ^[1]

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1. Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

Femtosecond pump--probe techniques combined with a reflectron time-of-flight mass spectrometer are utilized to study the ultrafast reaction dynamics of the electronically excited [ital [tilde A]] state of ammonia clusters. All of the detected protonated cluster ions, (NH[sub 3])[sub [ital n]]H[sup +] [ital n]=2[minus]6, are observed to display two distinct features with respect to preselected pump--probe time delays; a fast decay, followed by a persistent ion signal leveling off to a finite nonzero value. The fast decay is attributed to a predissociation process; while an intracluster reaction, which leads to formation of long-lived intermediates (NH[sub 3])[sub [ital n]]NH[sub 4], is responsible for the nonzero falling off regime. The results provide conclusive experimental evidence that both an absorption--ionization--dissociation mechanism and an absorption--dissociation--ionization mechanism are operative in the [ital [tilde A]] state of ammonia clusters.

• DOE Contract Number: FG02-88ER60668; FG02-88ER60648
• OSTI ID: 6487305
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 99:1; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ABSORPTION
AMMONIA
CHEMICAL REACTIONS
DISSOCIATION
ENERGY LEVELS
EPITHERMAL REACTORS
EXCITED STATES
FAST REACTORS
HYDRIDES
HYDROGEN COMPOUNDS
ION PAIRS
IONIZATION
MASS SPECTROMETERS
MEASURING INSTRUMENTS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
PULSES
REACTORS
SORPTION
SPECTROMETERS
TIME-OF-FLIGHT METHOD