Negative Ions In Space

在外层空间，例如在恒星之间的分子云和恒星周围的分子壳中，已经检测到了一百多种不同的分子，如水和乙醇。去年12月（2006年）首次发现了一种新型分子，这促使了这项研究。分子是由原子组成的，原子是由一个带正电的“重”核组成的，在中心被一个电子“云”包围，电子比原子核轻数千倍，带负电。正常情况下，来自每个原子的电子的负电荷正好与每个原子核的正电荷平衡，因此分子是中性的。然而，如果一个电子被拿走，分子就带正电，被描述为带正电的分子离子。或者，如果一个额外的电子被添加到分子中，它将具有总的负电荷，并被描述为带负电荷的分子离子。在太空中探测到的所有分子都是中性或带正电荷的分子离子，直到去年12月（2006年），第一个带负电荷的分子离子在星星周围的分子壳层和恒星之间的分子云中被发现。天文学家获得的证据表明这种负离子的存在是非常强有力的，因为他们用望远镜观察到了相同的特征信号，他们在实验室的实验中也观察到了这种负分子离子。第二个带负电荷的分子离子在2007年5月被报道。该项目的目的是研究使分子带负电荷所需的额外电子可以附着在分子上的不同方式。事实证明，电子是如此之小，以至于它的运动与网球和汽车等日常物体的运动不同。有必要使用基于“量子力学”的计算方法来确定分子附近电子的运动。在这个项目中，将使用一个计算机程序来计算在空间中发现的分子附近的电子运动。实验室还将进行实验，以研究在太空中发现的电子和分子之间的碰撞中如何形成负离子。在太空中发现的将在该项目中进行检查的分子无法从化学公司购买，因此在进行检查之前，有必要通过仔细控制的化学反应来制造它们。

Over a hundred different molecules such as water and ethanol have been detected in outer space in, for example, molecular clouds between the stars and in molecular shells that surround stars. Last December (2006) a new type of molecule was detected for the first time that has prompted this investigation. Molecules are made up of atoms which are made up of a positively charged 'heavy' nucleus at the centre surrounded by a 'cloud' of electrons which are thousands of times lighter than the nucleus and negatively charged. Normally the negative charge of the electrons from each atom exactly balances the positive charge of each nucleus so that the molecule is neutral. If, however, an electron is taken away the molecule becomes positively charged and is described as a positively charged molecular ion. Alternatively, if an extra electron is added to the molecule it t will have an overall negative charge and is described as a negatively charged molecular ion. All the molecules detected in space were either neutral or positively charged molecular ions until last December (2006) when the first negatively charged molecular ion was discovered in the shell of molecules surrounding a star and in a molecular cloud in between the stars. The evidence obtained by astronomers for the presence of this negative ion was very strong because they observed the same characteristic signal with a telescope that they had also observed from this negative molecular ion in an experiment in their laboratory. A second negatively charged molecular ion was reported in May (2007).The aim of this project is to examine different ways in which the extra electron required to make the molecules negatively charged could become attached to the molecule. It turns out that the electron is so small that its movement is unlike the movement of everyday objects, such as tennis balls and cars. It is necessary to use a method of calculation based on 'Quantum Mechanics' to determine the motion of an electron near a molecule. In this project, a computer programme will be used to calculate the motion of the electron near molecules found in space. Experiments will also be performed in the laboratory to investigate how negative ions are formed in collisions between electrons and molecules found in space. The molecules found in space that will be examined in the project are not available to buy from chemical companies so it will be necessary to make them with carefully controlled chemical reactions before they can be examined.