Table 6
Column density estimates of CH3CN in the NGC 7538 survey according to the partition function computed in the present work (rovibra-tional partition functions are computed as the product of the rotational contribution, given as a direct sum, and the harmonic approximation of the vibrational partition function) and in the CDMS and JPL databases.
| Linear interpolation(a) | Nonlinear interpolation(c) | Present work(d) | |||||
|---|---|---|---|---|---|---|---|
| CH3CN | Present work | CDMS | Rel. Diff. (b) | Present work | CDMS | Rel. Diff. (b) | |
| Q(T = 350 K) | 13810.0 | 11584.6 | 11139.0 | 10264.2 | 11209.6 | ||
| N (cm−2) | (53.1±3.5) × 1013 | (44.5±3.0) × 1013 | 18% | (42.8±2.9) × 1013 | (39.5±2.6) × 1013 | 8% | (43.1±2.9) × 1013 |
Notes. The interpolated partition function at the excitation temperatures deduced (350.33 K) is compared with the value computed in the present work. (a)The linear interpolation was carried out using the values of Qrv at T = 300 K and 500 K. (b)Relative difference between the column density estimates obtained from the partition functions computed in the present work and those given in the CDMS and JPL catalogs, using the formalism 
.(c) The nonlinear interpolation was carried out with the fitted sixth-order polynomial expansion of Qrv in terms of the temperature. The polynomial coefficients for the partition function of this work are given in Col. 2 of Table 5. (d)Partition function computed with Eqs. (1) and (2) for the excitation temperature deduced for the NGC 7538 survey and provided in Table D.2, available at the CDS.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.