Absorption Spectra of Acrolein and Crotonaldehyde and Dissociation Reaction
for Production of Fragment HCO
Mei-Lin Ho (何美霖)a, Sheng-Jui Lee (李昇叡)a, Hsiao-Chi Lu (盧曉琪)b,
Hong-Kai Chen (陳宏凱)b, Bing-Ming Cheng (鄭炳銘)b, I-Chia Chen (陳益佳)a
a
Department of Chemistry, National Tsing-Hua University, Hsinchu, Taiwan
b
Synchrotron Radiation Research Center, Hsinchu, Taiwan
With development of industry technology, various gases from complex and diverse chemical
reactions from the factory exhaust have been released into the atmosphere. Aldehydes are the
pollutants of the troposphere in the atmosphere. Study of the photochemistry reactions of
aldehydes provides the information for understanding the behavior of aldehydes in the atmosphere.
The 6m-CGM VUV beamline is used to measure absorption cross-section of molecules at resolution
0.1Å. The samples include arolein, metharolein, crotonaldehydes, glyoxal and cyclopentanone. We
also employ ab initio calculations to estimate the energies of the Rydberg states and the highly
excited electronic states to confirm the assignments of these spectra. By employing laser
photolysis/laser-induced fluorescence (LIF) and pump-probe techniques, acrolein and
crotonaldehyde are photolysed at 193 nm. A tunable dye laser pumped by a YAG laser generates
the probe beam to excite products (HCO). Fluorescence from fragment HCO is detected via
~
excitation to the excited state B 2 A ' . We found that no detectable HCO is generated from
crotonaldehyde, but intense HCO LIF signal is detected from acrolein after 193 nm photolysis.