Table 2.
X-ray photodesorption yields at 564 eV of methanol and photoproducts from pure methanol ice (from Paper I) and 13CO:CH3OH and H2O:CH3OH mixture ices at 15 K and for a dose between 5 × 1015 and 2 × 1016 photon cm−2.
Photodesorption yields in 10−3 molecule/photon | 13CO:CH3OH ice |
H2O:CH3OH ice |
|||
---|---|---|---|---|---|
Mass – photodesorbed species | Pure CH3OH | 1:1 | 6:1 | 1.5:1 | 3:1 |
30 – H2CO | 1.2±0.5 | NM ( * ) | NM ( * ) | 1.1±0.5 | 2.3±0.9 |
31 – H![]() |
< 0.5 | 8.8±1.8 | |||
32 – CH3OH (1) | 7.6±0.9 | 4.8±0.5 | 13±2 | ND ( * *) | ND ( * *) |
33 – 13CH3OH | 0.3±0.1 | 0.8±0.3 | |||
46 – HCOOH, C2H6O isomers (2) | 0.8±0.3 | 1.5±0.8 | 3.5±1.8 | ND ( * *) | ND ( * *) |
47 – H13COOH, 13C12CH6O isomers | 0.5±0.1 | 4.2±0.8 |
Notes. As explained in Sect. 3.2, these yields are corrected for the dilution factor of the corresponding parent molecule for 13CO:CH3OH and H2O:CH3OH ices. ( * )NM = Not measured: we did not measure the corresponding mass in the QMS for the ice considered. ( * *)ND = Not detected: the desorption signal measured for the considered species is below our signal-to-noise ratio, meaning that we did not detect its desorption from the ice. Considering the noise profile on the mass channel 32 and 46 of our QMS, if photodesorption from H2O:CH3OH ice occurs in these channels, the photodesorption yield is < 5 × 10−4 molecule/photon. (1)These yields are estimated using the signal on the mass channel 31 (see Sect. 3.2 for more details) (2)The photodesorption yields derived for the mass 46 on the 13CO:CH3OH mixtures are not corrected for any possible cracking of the mass 47 in the QMS as no identification is possible for the molecules corresponding to the mass 47.
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