You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Spur reactions observed by picosecond pulse radiolysis in highly concentrated bromide aqueous solutions. The formation of the well-known product Br3(-), observed in the steady-state radiolysis of highly concentrated Br(-) aqueous solutions, has now been directly observed at ultrashort times corresponding to the relaxation of the spur. The transient absorption induced by picosecond pulse radiolysis of 6 M Br(-) aqueous solution was probed simultaneously at 260 nm with the third harmonic laser wave and from 350 to 750 nm with a supercontinuum generated by the fundamental laser wave. This approach allows several transient radiolytic species to be followed in parallel, particularly the solvated electron, BrOH(-•), Br2(-•), and Br3(-). The kinetics measured within 4 ns at 260 and 370 nm clearly exhibit that the decay of Br2(•-) is correlated with the formation of Br3(-). In highly concentrated Br(-) solutions, the OH(•) radical is fully replaced by Br2(•-), and the spur kinetics of OH(•) radical in pure water is comparable with that of Br2(-•). Model calculations indicate that the main OH(•) radical combination product H2O2 in pure water has formation kinetics similar to that of Br3(-) in 6 M Br(-) solutions. Moreover, they point out that oxidation of Br(-) occurs within the electron pulse both by direct energy absorption and by scavenging of the water radical cation, H2O(•+).
{"Chemical": ["H2O(\u2022+)", "H2O2", "Br3(-)", "Br(-)", "Br2(\u2022-)", "bromide", "Br2(-\u2022)", "OH(\u2022)", "BrOH(-\u2022)"]}