Rydberg state photochemistry of 1,4-diazabicyclo(2. 2. 2)octane excited by 193- and 248-nm lasers

Journal Article · Thu May 21 04:00:00 EDT 1987 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100295a020· OSTI ID:6508643

Lin, C T

Linear and nonlinear photochemistries of 1,4-diazabicyclo(2.2.2)octane (DABCO) are investigated at room temperature by using ArF (193 nm) and KrF (248 nm) lasers. With an unfocused beam geometry, DABCO vapor displays a strong fluorescence when excited at 248 nm, but it shows no detectable emission with 193-nm excitation. The linear photochemistry quantum yield for DABCO is determined as phi/sub p/(248nm) approx. 0.1 and phi/sub p/(193 nm) approx. 0.3. The main stable photochemical products are analyzed as C/sub 2/H/sub 4/ and C/sub 2/H/sub 2/ for 248- and 193-nm excitation, respectively. When focused beam excitation is used, both ArF and KrF lasers dissociate DABCO molecules and give three strong radical emissions of CN*(B vector /sup 2/..sigma.. ..-->.. X vector /sup 2/ ..sigma../sup +/), CH*(A vector /sup 2/..delta.. ..-->.. X vector /sup 2/II), and C/sub 2/*(D vector /sup 3/II/sub g/ ..-->.. a vector /sup 3/II/sub u/). The time behavior, the laser power dependence, and the sample pressure dependence of these emissive radicals are examined. The possible mechanisms for the Rydberg state photochemistry of DABCO are discussed.

• Research Organization: Northern Illinois Univ., DeKalb
• OSTI ID: 6508643
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 91:11; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
42 ENGINEERING
420300 -- Engineering-- Lasers-- (-1989)
ALKANES
AZIDO COMPOUNDS
CHEMICAL REACTIONS
CHEMISTRY
DATA
EFFICIENCY
EMISSION SPECTROSCOPY
ENERGY LEVELS
EXCIMER LASERS
EXCITED STATES
EXPERIMENTAL DATA
FLUORESCENCE SPECTROSCOPY
GAS LASERS
HYDROCARBONS
INFORMATION
LASERS
NUMERICAL DATA
OCTANE
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOCHEMISTRY
PRESSURE DEPENDENCE
QUANTUM EFFICIENCY
REACTION INTERMEDIATES
RYDBERG STATES
SPECTROSCOPY
TIME DEPENDENCE