Why do neon lights give off colorful lights?

Why do neon lights give off colorful lights?Do you know the principle?

When the night falls, the streets of the city are lit up with colorful neon lights, which make the whole city look particularly beautiful at night, showing the scene of urban prosperity.Why do neon lights have this name?That's where it comes from.

Back in 1898, British chemists Remsay and Travers, after chemically removing oxygen and nitrogen from the air, discovered a strange and rare gas in liquid air.When this gas is sealed in a semi-vacuum glass tube and an electric current is applied to both ends of the glass tube, the previously colourless glass tube glows red.They called this newly discovered gas "neon", which means "new" in Greek. The Greek word for "new" means "neon", which means "neon" in Greek. So this "new light" is called "neon".And so neon was born.

Later, people think that only red neon is too drab, so has invented the blue, green, white, yellow, purple colored phosphors, blue phosphors besmear is on glass tube, on the inner wall of the glass tube bending after made the required words or patterns, fitted with electrodes, and the glass tube air pumping clean, put in neon, neon lights will be a pink;When argon and mercury are placed in a tube coated with blue phosphor, the neon lights emit bright blue.A neon gas placed in a tube coated with green phosphor is orange-red;If you change neon to argon and mercury, a neon light will glow green.Through different combinations, the electrified neon lights can emit colorful light.

The luminous principle of neon lights when electrified is similar to that of sky lightning, which is also a phenomenon of gas discharge.When the tube is energized, the gas molecules gain energy and are continuously ionized into free electrons (negatively charged) and positive ions (positively charged).At the same time, the opposite process is going on, where the positive ions combine with the electrons to form molecules.In the process of recombination, excess energy is released in the form of light energy.Different gas molecules, due to the composition and structure of different, the amount of light energy emitted from the compound is different, so that a variety of colors will appear.