Scientists have isolated the two different forms of water molecule for the first time.

近日，科学家们首次成功分离出两种不同形式的水分子。
Water molecules were known to exist as two distinct "isomers", or types, based on their slightly different properties at the atomic level.
基于原子水平上略微不同的性质，已知的水分子可以以两种不同的“异构体”类型存在。
By separating out the two isomers, researchers were able to show that they behave differently in the way that they undergo chemical reactions.
通过分离出两种异构体，研究人员能够证明它们在进行化学反应时可以表现出不同的行为。
In basic terms, water molecules consist of a single oxygen atom bonded to a pair of hydrogen atoms.
简言之，水分子是由两个氢原子和一个氧原子键合而成的。
However, they can be further subdivided based on a property of the nuclei at the hearts of the hydrogen atoms - their "spin".
但是，它们可以根据氢原子核心“自旋”的特性进一步细分。
While they aren't spinning in the sense we would understand, this property of hydrogen nuclei does affect the rotation of the water molecules themselves.
虽然这不是我们普通理解意义上的旋转，但氢核的这种属性确实会影响水分子本身的旋转。
科学家发现水分子其实有两种类型

If the nuclear spins of the two hydrogen atoms in water are oriented in the same direction, it is called ortho-water. If they are arranged in different directions, it is known as para-water.

如果水分子中的两个氢原子核自旋以相同的方向取向，则称为正水分子。如果他们异向自旋，则被称为负水分子。
Given that the isomers are very similar, it has been particularly challenging to separate them out. But co-author Prof Stefan Willitsch and his colleagues succeeded in doing it using electric fields.
鉴于异构体非常相似，所以将它们分开非常具有挑战性，但Stefan Willitsch教授和他的同事成功地利用电场进行了水分子分离。
They were then able to investigate how the different forms of water reacted with another chemical.
随后，他们就能够研究不同形式的水分子与另一种化学品的反应情况。
They used ultracold diazenylium ions (a form of nitrogen) for this test. The researchers found that para-water reacted about 25% faster with the diazenylium than ortho-water.
他们使用氮离子（一种氮的形式）进行了这项测试。研究人员发现，与正水分子相比，负水分子化学反应速度提高了25％左右。
Because the rotation of H2O molecules is affected by the nuclear spin, different attractive forces act between the partners in this chemical reaction.
由于水分子的旋转受到核自旋的影响，所以在这种化学反应中，不同的吸引力在相互反应之间起了作用。
Prof Willitsch said the research could help improve control over other kinds of chemical reaction: "The better one can control the states of the molecules involved in a chemical reaction, the better the underlying mechanisms and dynamics of a reaction can be investigated and understood."
Willitsch教授表示，这项研究可以帮助改善对其他类型化学反应的控制：“我们可以更好地控制化学反应中水分子的状态，有利于更深入研究和理解反应的潜在机制和动力学。”

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