Chromophores. Molecules that absorb light at these wavelengths are called chromophores. Chromophores are functional groups of a molecule that absorb light in this UV-Visible region. They are most of the time characterized by delocalized pi electrons.
Blockers, absorbers, and windows
In sunscreen, ingredients that absorb UVA/UVB rays, such as avobenzone, oxybenzone and octyl methoxycinnamate, are organic chemical absorbers or "blockers". They are contrasted with inorganic absorbers/"blockers" of UV radiation such as titanium dioxide and zinc oxide.
Fluorescent substances are used in energy-efficient lamps - they absorb ultraviolet light produced inside the lamp, and re-emit the energy as visible light. Similar substances are used on bank notes to detect forgeries.
Ozone is a particularly effective absorber of UV radiation. As the ozone layer gets thinner, the protective filter activity of the atmosphere is progressively reduced.
Protect your skin with clothing that covers your arms and legs. Wear a wide-brimmed hat to protect your head, face, and neck. Wear sunglasses that block UV rays to protect your eyes and the skin around them. Use sunscreen with at least SPF 30 to help protect skin that isn't covered with clothing.
Some popular UV stabilizers of this type are: carbon black (which is the most common one thanks to its black color), rutile titanium oxide (which is effective in the 300 - 400 nm range but work less efficiently in the short wavelength ranging below 315), hydroxybenzophenone, hydroxyphenyl benzotriazole (this type is ...
The most common fluorescent minerals include calcite, fluorite, and sodalite – though there are many others. Many gemstones (such as diamond, ruby, emerald, amber, and opal) will also fluoresce when exposed to UV light.
Melanin absorbs UV radiation and reduces the UV-induced damage in the melanocytes and keratinocytes.
Examples are organic compounds containing nitrogen, oxygen, or halogens. As n electrons can be excited by UV radiation, any compound that contains atoms like nitrogen, oxygen, sulphur, halogen compounds or unsaturated hydrocarbons may absorb UV radiation.
Although both chlorophyll a and chlorophyll b absorb light, chlorophyll a plays a unique and crucial role in converting light energy to chemical energy (as you can explore in the light-dependent reactions article).
Semen fluoresces blue between 300-450 nm, in the ultraviolet range. Most fluids must be dry before they exhibit fluorescence. A possible exception would be urine. Depending on the composition and quantity of nutrient intake, certain compounds could be expelled which fluoresce in their liquid state.
ULTRAVIOLET LIGHT FROM OUR SUN
UV-B rays are the harmful rays that cause sunburn. Exposure to UV-B rays increases the risk of DNA and other cellular damage in living organisms. Fortunately, about 95 percent UV-B rays are absorbed by ozone in the Earth's atmosphere.
Many commercial glass materials will also absorb a significant amount of UV-A wavelengths, but we are aware of some "quartz glass" materials which are commonly known to have a high rate of UV transmission.
UV is a range of wavelengths. At the upper bands, short wavelengh UV light, many gas molecules absorb UV light. Water, Oxygen even Nitrogen.
Ozone occurs both in the Earth's upper atmosphere and at ground level. Ozone can be good or bad, depending on where it is found. Called stratospheric ozone, good ozone occurs naturally in the upper atmosphere, where it forms a protective layer that shields us from the sun's harmful ultraviolet rays.
Hence the energy of UV radiation is absorbed in ozone layer even before reaching earth's surface. That's how ozone layer protects us from UV radiation.
Fabrics with darker or more intense colors tended to have better UV absorption. Deep blue shades offered the highest absorption, while yellow shades offered the least. Clothing manufacturers could use information from this study to better design sun-protective clothing, the scientists indicate.
Chlorophyll. The green pigment in leaves is chlorophyll, which absorbs red and blue light from sunlight.
Plastics and movies are often used in window films, car windshields, and other products to help reduce the amount of UV light entering a space. Glass is also an excellent option for absorbing UV light, as it is often able to block up to 99.9% of the UV rays.
It is estimated that around 50% of all diamonds have fluorescence that can be seen in special conditions e.g. under a long wave UV lamp, while around 10% fluoresce strongly enough to make a noticeable difference to the colour of the diamond when viewed in sunlight or incandescent (low UV) light.
Conclusion: Titanium dioxide and zinc oxide provide UV protection primarily via absorption of UV radiation and not through significant reflection or scattering.
UV absorbers absorb UV and convert it into heat or other forms of energy to prevent UV from penetrating into skin.
The best sunscreen ingredients — zinc oxide and titanium dioxide. When it comes to choosing a sunscreen, Dr. Davis recommends two mineral ingredients — zinc oxide and titanium dioxide. These are the main ingredients in many physical sunscreens and provide effective, long-lasting protection from both UVA and UVB light.
UV can easily be shielded by materials such as polycarbonate, metal, cardboard, and wood. Ordinary glass blocks most UV light of wavelengths less than 330 nm but may also transmit most of the UV for longer wavelengths.