Nonlinear optics may solve long-standing astrophysical puzzle

Diffuse interstellar bands (DIBs), optical phenomena that have perplexed scientists for more than 70 years, may be caused by nonlinear absorption of molecular hydrogen, according to Jim Glownia and Peter Sorokin of IBM Research Division (Yorktown Heights, NY), who presented their theory at CLEO/QELS `96 (paper QFC1). A complex pattern of more than 200 absorption bands with varying widths, DIBs are detected in the visible portion of the spectrum of reddened bright stars. Previous theories include

Nonlinear optics may solve long-standing astrophysical puzzle

Diffuse interstellar bands (DIBs), optical phenomena that have perplexed scientists for more than 70 years, may be caused by nonlinear absorption of molecular hydrogen, according to Jim Glownia and Peter Sorokin of IBM Research Division (Yorktown Heights, NY), who presented their theory at CLEO/QELS `96 (paper QFC1). A complex pattern of more than 200 absorption bands with varying widths, DIBs are detected in the visible portion of the spectrum of reddened bright stars. Previous theories include the presence of inorganic impurities, fullerenes, large organic molecules related to life, and alien bacteria.

A thin interstellar cloud of hydrogen near a reddened star absorbs that body`s vacuum ultraviolet emissions, causing electrons to jum¥from optically pumped states to higher-level singlet states. More than 70 of the 130 known narrowband DIB features can be matched to well-defined transitions to within 0.07 cm-1. Such correlation is unlikely to occur by chance--Glownia suggests that, given the density of the appropriate hydrogen states, a conservative estimate of the probability of a chance coincidence is about 1 in 100.

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