Abstract
We report oscillator strengths for six strong vibrational bands between 105.0 and 115.2 nm, associated with transitions from the v = 0 level of the X 1Σ+ ground state to the v = 0 and 1 levels of the B 1Σ+, C 1Σ+, and E 1Π states, in 12C16O, 12C 17O, 12C18O, 13C16O, and 13C18O. These measurements extend the development of a comprehensive database of line positions, oscillator strengths, and linewidths of photodissociating transitions for all astrophysically relevant CO isotopologues. The E-X bands, in particular, play central roles in CO photodissociation and fractionation models of interstellar clouds and circumstellar disks including the early solar nebula. The resolving powers of the room-temperature measurements, R = 300,000-400,000, allow for the analysis of individual line strengths within bands; the measurements reveal J-dependences in the branch intensities of the C(v = 0,1)-X(0) and E(v = 0,1)-X(0) bands in all isotopologues. Minimal or no isotopologue dependence was found in the f-values of the C(v = 0,1)-X(0) and E(v = 0,1)-X(0) bands at a ∼5% uncertainty level. Revised dissociation branching ratios for the C(v = 0,1) and E(v = 0,1) levels are computed based on these f-values. The weak isotopologue dependence of the f-values presented here eliminates this mechanism as an explanation for the large 17O enrichments seen in recent laboratory photolysis experiments on CO at wavelengths from 105 to 108 nm.
Original language | English (US) |
---|---|
Article number | 67 |
Journal | Astrophysical Journal |
Volume | 788 |
Issue number | 1 |
DOIs | |
State | Published - Jun 10 2014 |
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Keywords
- ISM: molecules
- methods: laboratory: molecular
- molecular data
- techniques: spectroscopic
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science
Cite this
High-resolution oscillator strength measurements of the v′ = 0,1 bands of the B-X, C-X, and E-X systems in five isotopologues of carbon monoxide. / Stark, G.; Heays, A. N.; Lyons, James; Smith, P. L.; Eidelsberg, M.; Federman, S. R.; Lemaire, J. L.; Gavilan, L.; De Oliveira, N.; Joyeux, D.; Nahon, L.
In: Astrophysical Journal, Vol. 788, No. 1, 67, 10.06.2014.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - High-resolution oscillator strength measurements of the v′ = 0,1 bands of the B-X, C-X, and E-X systems in five isotopologues of carbon monoxide
AU - Stark, G.
AU - Heays, A. N.
AU - Lyons, James
AU - Smith, P. L.
AU - Eidelsberg, M.
AU - Federman, S. R.
AU - Lemaire, J. L.
AU - Gavilan, L.
AU - De Oliveira, N.
AU - Joyeux, D.
AU - Nahon, L.
PY - 2014/6/10
Y1 - 2014/6/10
N2 - We report oscillator strengths for six strong vibrational bands between 105.0 and 115.2 nm, associated with transitions from the v = 0 level of the X 1Σ+ ground state to the v = 0 and 1 levels of the B 1Σ+, C 1Σ+, and E 1Π states, in 12C16O, 12C 17O, 12C18O, 13C16O, and 13C18O. These measurements extend the development of a comprehensive database of line positions, oscillator strengths, and linewidths of photodissociating transitions for all astrophysically relevant CO isotopologues. The E-X bands, in particular, play central roles in CO photodissociation and fractionation models of interstellar clouds and circumstellar disks including the early solar nebula. The resolving powers of the room-temperature measurements, R = 300,000-400,000, allow for the analysis of individual line strengths within bands; the measurements reveal J-dependences in the branch intensities of the C(v = 0,1)-X(0) and E(v = 0,1)-X(0) bands in all isotopologues. Minimal or no isotopologue dependence was found in the f-values of the C(v = 0,1)-X(0) and E(v = 0,1)-X(0) bands at a ∼5% uncertainty level. Revised dissociation branching ratios for the C(v = 0,1) and E(v = 0,1) levels are computed based on these f-values. The weak isotopologue dependence of the f-values presented here eliminates this mechanism as an explanation for the large 17O enrichments seen in recent laboratory photolysis experiments on CO at wavelengths from 105 to 108 nm.
AB - We report oscillator strengths for six strong vibrational bands between 105.0 and 115.2 nm, associated with transitions from the v = 0 level of the X 1Σ+ ground state to the v = 0 and 1 levels of the B 1Σ+, C 1Σ+, and E 1Π states, in 12C16O, 12C 17O, 12C18O, 13C16O, and 13C18O. These measurements extend the development of a comprehensive database of line positions, oscillator strengths, and linewidths of photodissociating transitions for all astrophysically relevant CO isotopologues. The E-X bands, in particular, play central roles in CO photodissociation and fractionation models of interstellar clouds and circumstellar disks including the early solar nebula. The resolving powers of the room-temperature measurements, R = 300,000-400,000, allow for the analysis of individual line strengths within bands; the measurements reveal J-dependences in the branch intensities of the C(v = 0,1)-X(0) and E(v = 0,1)-X(0) bands in all isotopologues. Minimal or no isotopologue dependence was found in the f-values of the C(v = 0,1)-X(0) and E(v = 0,1)-X(0) bands at a ∼5% uncertainty level. Revised dissociation branching ratios for the C(v = 0,1) and E(v = 0,1) levels are computed based on these f-values. The weak isotopologue dependence of the f-values presented here eliminates this mechanism as an explanation for the large 17O enrichments seen in recent laboratory photolysis experiments on CO at wavelengths from 105 to 108 nm.
KW - ISM: molecules
KW - methods: laboratory: molecular
KW - molecular data
KW - techniques: spectroscopic
UR - http://www.scopus.com/inward/record.url?scp=84901772486&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84901772486&partnerID=8YFLogxK
U2 - 10.1088/0004-637X/788/1/67
DO - 10.1088/0004-637X/788/1/67
M3 - Article
AN - SCOPUS:84901772486
VL - 788
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 1
M1 - 67
ER -