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Infrared Multiphoton Absorption by Methanol
Author(s) -
Evans D. K.,
Mcalpine Robert D.,
Adams H. M.
Publication year - 1984
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.198400032
Subject(s) - chemistry , fluence , laser , absorption (acoustics) , absorption spectroscopy , atomic physics , full width at half maximum , methanol , ultrafast laser spectroscopy , analytical chemistry (journal) , optics , physics , organic chemistry , chromatography
The multiphoton absorption of CO 2 laser 9 μm P(18), P(20) and P(34) lines by methanol has been studied for fluences from 10 −3 to ∼ 20 J/cm 2 , pulse widths of 6 and 60 ns FWHM and methanol pressures from 0.067 to 13.3 kPa. The absorption depends on laser fluence, laser line and gas pressure but not on laser beam intensity. For each line studied the results can be expressed as a function of fluence and the product of pressure with pulse width. Absorption by a Q ‐branch transition (9P(34) pumping) shows a faster relaxation and a stronger absorption than R‐branch transitions (9P(18) and 9P(20) pumping). The results obtained here are compared to multiphoton absorption data for an HF laser pumping the OH stretch vibration.