Ab initio g-tensor calculations of hydrogen bond effects on a nitroxide spin label

Citation
M. Engstrom et al., Ab initio g-tensor calculations of hydrogen bond effects on a nitroxide spin label, CHEM P LETT, 338(4-6), 2001, pp. 407-413
Citations number
24
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
CHEMICAL PHYSICS LETTERS
ISSN journal
0009-2614 → ACNP
Volume
338
Issue
4-6
Year of publication
2001
Pages
407 - 413
Database
ISI
SICI code
0009-2614(20010427)338:4-6<407:AIGCOH>2.0.ZU;2-V
Abstract
Hydrogen bonding effects on the electron paramagnetic resonance (EPR) g-ten sor of a nitroxide spin label was investigated by quantum chemical calculat ions. The restricted open-shell Hartree-Fock (ROHF) linear response method with the atomic mean field approximation (AMFI) was used in the calculation s. The results show that hydrogen bonding reduces the g-tensor component di rected along the NO bond, g(xx). This decrease is traced to higher excitati on energy and lower spin-orbit coupling and angular momentum matrix element s for the n-pi* excitation. The calculations show that the g-tensor is prac tically invariable when hydrogen bonding was modeled with methanol instead of water. (C) 2001 Elsevier Science B.V. All rights reserved.