<unk> : The chromophore absorbs UV-light (* denotes an excited state), and the energy of the excited state is creating singlet oxygen (1O2) or a hydroxyl radical (•OH), which then damages DNA through oxidation.<unk>  occurs when a UV-photon is absorbed in the human skin by a chromophore that does not have the ability to convert the energy into harmless heat very quickly. Molecules that do not have this ability have a long-lived excited state. This long lifetime leads to a high probability for reactions with other molecules—so-called bimolecular reactions. Melanin and DNA have extremely short excited state lifetimes in the range of a few femtoseconds (10−15s). The excited state lifetime of compounds used in sunscreens such as menthyl anthranilate, avobenzone or padimate O is 1,000 to 1,000,000 times longer than that of melanin, and therefore they may cause damage to living cells that come in contact with them. The molecule that originally absorbs the UV-photon is called a "chromophore". Bimolecular reactions can occur either between the excited chromophore and DNA or between the excited chromophore and another species, to produce free radicals and reactive oxygen species. These reactive chemical species can reach DNA by diffusion and the bimolecular reaction damages the DNA (oxidative stress). It is important to note that, unlike direct DNA damage which causes sunburn,<unk>  does not result in any warning signal or pain in the human body. The bimolecular reactions that cause the<unk>  are illustrated in the figure: : 1O2 is reactive harmful singlet oxygen: :
Indirect DNA damage
Direct DNA damage
DNA replication stress
DNA fragmentation
Viral interference
Copy number variation
DNA repair-deficiency disorder
Radiation damage