Crossed-beam reaction of C({sup 3}{ital P}{sub {ital j}}) with C{sub 2}H{sub 2}({sup 1}{summation}{sup +}{sub g}): Observation of tricarbon-hydride C{sub 3}H
- Department of Chemistry, University of California and Chemical Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
The reaction between ground state carbon atoms, C({sup 3}{ital P}{sub {ital j}}), and acetylene, C{sub 2}H{sub 2}({sup 1}{summation}{sup +}{sub {ital g}}), was studied at an average collision energy of (8.4{plus_minus}0.3) kJ mol{sup {minus}1} using the crossed molecular beam technique. The product angular distribution and time-of-flight spectra of {ital m}/{ital z}=37, i.e., C{sub 3}H, were recorded. Only {ital m}/{ital z}=37 was detected, but no signal from the thermodynamically accessible C{sub 3}({sup 1}{summation}{sup +}{sub {ital g}})+H{sub 2}({sup 1}{summation}{sup +}{sub {ital g}}) channel. Forward-convolution fitting of the results yielded a center-of-mass angular flux-distribution forward scattered in respect to the carbon beam, whereas the translational energy flux distribution peaked at only (5.4{plus_minus}1.2) kJ mol{sup {minus}1}, suggesting a simple C--H-bond-rupture to H+C{sub 3}H. The reaction likely proceeds on the triplet surface with an entrance barrier to the C{sub 3}H{sub 2}--PES of {lt}(8.4{plus_minus}0.3) kJ mol{sup {minus}1} via addition of the carbon atom to two bonding {pi}-orbitals located both at C1 or at C1 and C2 of the acetylene molecule. The explicit identification of C{sub 3}H product under single collision conditions strongly demands incorporation of atom-neutral reactions in reaction networks simulating chemistry in the interstellar medium, in interstellar shock waves, and in outflows of carbon stars. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 132853
- Journal Information:
- Journal of Chemical Physics, Vol. 103, Issue 23; Other Information: PBD: 15 Dec 1995
- Country of Publication:
- United States
- Language:
- English
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