Infrared photodissociation of small methanol clusters

✍ Scribed by Friedrich Huisken; Martin Stemmler

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 468 KB
• Volume: 144
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(88)87135-5

✦ Synopsis

A continuous supersonic molecular beam of small methanol clusters is crossed by the radiation of a pulsed CO2 laser. Subsequent scattering by a secondary He beam disperses the cluster beam and allows the off-axis detection of selected cluster species, undisturbed by ionizer fragmentation artifacts. In the region of the yg C-O stretching vibration, the dependence of IR photon absorption on laser frequency and fluence is investigated as a function of cluster size. The predissoeiation spectrum of the dimer shows two distinct peaks at 1026.5 and 1051.6 cm-' which correspond to the excitation of the two non-equivalent monomers in the dimer. The trimer spectrum features one single peak centered at 1042.2 cm-'. This is consistent with a cyclic structure in which all three methanol molecules are equivalent. Higher cluster spectra are characterized by single peaks gradually blue-shifted with respect to the trimer line.