TY - JOUR
T1 - Dynamic processes of olefins adsorbed on hydroxyl groups of DM20 zeolite excited by picosecond infrared pulses
T2 - Vibrational relaxation, short-lived species and desorption
AU - Onda, Ken
AU - Tanabe, Kinuka
AU - Noguchi, Hidenori
AU - Domen, Kazunari
AU - Wada, Akihide
PY - 2003/10/16
Y1 - 2003/10/16
N2 - We have investigated olefins adsorbed on Brønsted acidic hydroxyl groups (OD) of DM20 zeolite by transient infrared absorption spectra after excitation of the OD stretching mode using picosecond infrared lasers. The olefins studied were ethylene, deuterated ethylene, propylene, and isobutene, and only isobutene was adsorbed on OD at its methyl group while the other olefins were adsorbed at their double bonds. For all the olefins except isobutene, simple vibrational relaxation of the ν = 1 state was observed and the lifetimes were 2-4 ps. These lifetimes are an order faster than that of isolated OD. For isobutene, a long lifetime component lasting more than 500 ps was observed in addition to vibrational relaxation of 2 ps. The transient absorption spectra for isobutene-adsorbed zeolite at various time delays and frequencies indicated the existence of a short-lived species and a slow desorption process compared with vibrational relaxation.
AB - We have investigated olefins adsorbed on Brønsted acidic hydroxyl groups (OD) of DM20 zeolite by transient infrared absorption spectra after excitation of the OD stretching mode using picosecond infrared lasers. The olefins studied were ethylene, deuterated ethylene, propylene, and isobutene, and only isobutene was adsorbed on OD at its methyl group while the other olefins were adsorbed at their double bonds. For all the olefins except isobutene, simple vibrational relaxation of the ν = 1 state was observed and the lifetimes were 2-4 ps. These lifetimes are an order faster than that of isolated OD. For isobutene, a long lifetime component lasting more than 500 ps was observed in addition to vibrational relaxation of 2 ps. The transient absorption spectra for isobutene-adsorbed zeolite at various time delays and frequencies indicated the existence of a short-lived species and a slow desorption process compared with vibrational relaxation.
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U2 - 10.1021/jp030047h
DO - 10.1021/jp030047h
M3 - Article
AN - SCOPUS:0242380676
VL - 107
SP - 11391
EP - 11396
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
SN - 1520-6106
IS - 41
ER -