1.      A molecular iodine atlas in ascii format   Houssam Salami and Amanda Ross       Laboratoire de Spectrométrie Ionique et Moléculaire, Université Lyon I & CNRS (UMR 5579) Villeurbanne, France.
An invitation to use a Doppler-limited absorption spectrum, available on the Web …

2. Why record (yet another) spectrum of the B-X transitions of I2?
Not for the B-X spectroscopy of iodine! Only to calibrate excitation spectra.
The information already exists :
Aimé Cotton Atlas of Gerstenkorn and co-workers (in four parts).
In paper format
Corrections are required at short wavelengths.
Sub-Doppler Atlas (Katô and co-workers) « Hors Concours »
From tabulated parameters. (calculated spectrum, e.g.commercial Iodine Spec)

3. Our motivation : an excitation spectrum of NiH.
NiH fluorescence,
~17400 cm-1.
Nice spectrum. Inadequate wavemeter / temperature stabilized F-P fringes.

4. Recording the absorption spectrum of I2
Transmission spectrum recorded in 4 pieces (with appropriate optical filters).
Instrumental resolution cm-1.
50 cm iodine cell, heated according to wavelength region of interest.

5. I2 B-X absorption spectrum
Reference HeNe laser

6. Close Up … Doppler limited iodine lines still have odd shapes!

7. How does the calibration compare with other sources ?
Circles : LASIM – Aimé Cotton atlas
Triangles : LASIM – Katô atlas

8. Applied to an excitation spectrum of NiH
Comparison reveals non-linear scan of the laser, but calibration is quite feasible.
Q (2 ½)
Q (3 ½)

9. Conclusion
The spectrum was recorded to solve a local problem, but could probably prove useful elsewhere.
It is freely available …
We’re working on software to calibrate from this atlas automatically.
Has been submitted to Journal of Molecular Spectroscopy.