A photoabsorption and mass spectrometry study of pyrrole

Citation
Ee. Rennie et al., A photoabsorption and mass spectrometry study of pyrrole, CHEM PHYS, 250(2), 1999, pp. 217-236
Citations number
44
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
CHEMICAL PHYSICS
ISSN journal
0301-0104 → ACNP
Volume
250
Issue
2
Year of publication
1999
Pages
217 - 236
Database
ISI
SICI code
0301-0104(199912)250:2<217:APAMSS>2.0.ZU;2-O
Abstract
The absolute photoabsorption cross-section of pyrrole has been measured bet ween the ionisation threshold and 35 eV using a double ion chamber and mono chromated synchrotron radiation. An interpretation has been proposed for so me of the observed structure in terms of Rydberg series converging onto the (A) over tilde B-2(1) state threshold. In addition, the possibility that s everal broad features may be attributed to pi --> pi* transitions is discus sed. Time-of-flight mass spectra have been recorded for excitation energies between 11.8 and 77.5 eV, and appearance energies have been determined for seventeen fragment ions and the doubly charged parent ion. These have enab led, previously unknown, heats of formation to be estimated for five ions, including the doubly charged parent ion. A high resolution mass spectromete r, equipped with an electron impact ionisation source, has been used in B/E and B-2/E linked scanning modes to identify reactant/product pairings. Fra gmentation processes leading to the production of several high intensity fr agment ions have been modelled using ab initio and semi-empirical methods. (C) 1999 Elsevier Science B.V. All rights reserved.