Current status of the H-2 diffuse interstellar bands theory - Assignments of the lambda lambda 5780, 6284, 4428, 4882 large-equivalent-width diffuse interstellar bands

摘要

Major changes recently incorporated into the structure of the non-linear H-2 DIBs model (P. P. Sorokin and J. H. Glownia, Astrophs J., 1996, 473, 900) are outlined. To account for observed relative intensities of narrow DIBs assigned in the original model to H-2 inter-Rydberg transitions, it has become necessary to postulate a form of lightwave coherence existing in the H-2-containing cloud of the model, with numerous coherent 2n wave-mixing processes, each initiated by broadband stimulated Raman scattering (SRS), occurring on various H-2 transitions. By considering such wave-mixing processes, it becomes possible both to interpret archived VUV spectra of B-type supergiants and to easily assign large-equivalent-width DIBs (e.g. lambda lambda 5780, 6284, 4428, 4882) whose origins cannot be understood using the original 'passive' H-2 two-photon absorption model. The wave-mixing schemes discussed also enable one to understand why DIB intensities in given lines-of-sight correlate well with the amount of reddening observed in the same lines-of-sight. [References: 34]