Does the diiodide(1−) anion exist?

With respect to chemical bonding does the $\ce{I2-}$ ion exist?




I found a [paper](http://pubs.acs.org/doi/pdf/10.1021/jp0671087)$\ce{^{[1]}}$ regarding the formation of diiodide anion species($\ce{I2^-}$). It is assumed to be an unstable species which forms during the formation of triiodide anion (excess of iodide in solution which makes it brown). This is a part of the paper which describes the formation of the species. For more information, read the full paper. Also, you can check the abstract which @andselisk linked.



> 
> The $\ce{I2^-}$ species is formed by the 248-nm laser photolysis of
> iodide through the following reactions:
> 
> 
> $$\ce{I- + hν -> I + e\_s-}$$
> 
> 
> $$\ce{I + I- ->[k2]I2^-}$$
> 
> 
> $$\ce{I2- + I2- ->[k3]I3- + I-}$$
> 
> 
> As discussed later, we found that photodetachment of electrons from
> $\ce{I-}$ ions produces solvated electrons ($\ce{e\_s-}$) in ionic
> liquids as well as in molecular solvents. After photodetachment,
> iodine atoms react with $\ce{I-}$ to form diiodide anion radicals. In
> aqueous solution, the transient absorption maxima of $\ce{I2-}$ are
> located around 400 and 720 nm. The extinction coefficients of
> $\ce{I2-}$ in aqueous solution at 385 and 725 nm are 10000 and 2560
> M-1cm-1, respectively.[...]
> 
> 
> 


$\ce{^{[1]}}$: J. Phys. Chem. B, **2007**, 111 (18), pp 4807–4811


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