Uncovering the mechanism of photoexcited nucleobases: Is decay fast or suppressed?

The nucleobase molecules carrying the genetic codes are the most important ingredients for life, but they are also very vulnerable. When the ultraviolet component in the sunlight irradiates these molecules, the electrons in the molecules will be excited, and the excited nucleobase molecules may result in irreversible changes or even damages to the DNA and RNA chains, leading to the "sunburn" of organisms at molecular level.