Free electrons

Electrons move freely in a vacuum or in a substance. The electrons in the molecules that make up a substance are bound by a Coulomb field and are in a certain energy state. In contrast to bound electrons, electrons with a high degree of freedom are called free electrons. In order to explain the electrical properties of metals, H. Lorentz proposed a method of treating the electrons in metals as if they were free to move around like gas molecules, and since he succeeded in explaining many properties using quantum mechanics, this type of model has been called the free electron model. In addition, when a liquid is irradiated with radiation, the electrons that are ejected by ionization and move around in the liquid after escaping the Coulomb field of the positive ions that are generated at the same time are also called free electrons. When the liquid is water, the free electrons slow down at about ^10-12 s and become hydrated electrons surrounded by water molecules. Hydrated electrons become hydrogen atoms and hydroxide ions with a lifespan of about ^10-3 s. When the liquid is a hydrocarbon, they move freely in the liquid until they are captured by oxygen molecules or other positive ions present as impurities.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

真空中や物質中を自由に動きまわる電子．物質を構成している分子のなかの電子はクーロン場によって束縛され，一定のエネルギー状態にある．このような束縛された電子に対し，自由度の高い電子を自由電子と名づけている．金属の電気的性質を説明するために，H. Lorentzが金属中の電子は気体分子のように自由に飛びまわると仮定して取り扱う方法を提案し，量子力学によって多くの性質を説明することに成功して以来，このようなモデルを自由電子模型という．また，液体に放射線を照射したような場合，イオン化によって飛び出た電子が，そのとき同時に発生した正イオンのクーロン場から逃がれて液体中を動きまわるときも自由電子という．液体が水であるときは，自由電子は 10^－12 s 程度で減速し，水分子によって囲まれて水和電子となる．水和電子は 10^－3 s 程度の寿命で水素原子と水酸化物イオンになる．液体が炭化水素のときは，不純物として存在する酸素分子やほかの正イオンに捕そくされるまで自由に液体中を動きまわる．

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