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 -