Grant for Exploratory Research: Electric Field Induced Orientation of Rotationally Cooled Molecules

探索性研究资助：电场诱导旋转冷却分子的取向

• 批准号: 9016027
• 负责人: Dudley Herschbach
• 金额: $ 5万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-07-01 至 1991-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9016027&HistoricalAwards=false
• 关键词: Grant; Exploratory; Research; Electric; Field

Professor Dudley Herschbach is supported by a Small Grant for Exploratory Research from the Experimental Physical Chemistry Program to study molecular orientation in cold molecular beams by the application of strong electric fields. These measurements provide a new method to address questions concerning the importance of relative orientation between reacting molecules and the influence which molecular orientation has on chemical reactivity. Polar molecules with a three-fold or higher axis of symmetry in certain rotational states will precess in an electric field rather than tumble. The dipole moment therefore does not average out for such states, so an electric field can exert a torque which produces substantial orientation. Orientation by an electric field has been considered quite impractical for less symmetrical molecules. The rotational motion of diatomic, linear, or asymmetric top molecules averages out the dipole moment in first-order, so the interaction with an electric field is much weaker. Dr. Herschbach has performed feasibility calculations which show, however, that even in these cases only relatively modest Stark fields of 60,000 volts/cm are required to orient the lowest rotational states of linear molecules such as ICN when they are cooled to 2 degrees Kelvin in a molecular beam. This prediction, which Herschbach hopes to verify experimentally, would have an enormous impact on the whole field of reaction dynamics. It would provide an important new capability to study orientation effects in colliding molecular beams which would be achievable at easily attainable experimental conditions.

教授达德利赫施巴赫是由一个小补助金支持， 物理化学实验探究 冷分子束中分子取向的研究计划 通过强电场的应用。这些 测量提供了一种新的方法来解决问题 关于相对定向的重要性， 反应分子和影响分子 取向对化学反应性的影响。 具有三重或更高对称轴的极性分子， 在电场中某些转动态会发生旋进 而不是跌倒。 因此，偶极矩不 这样的状态是平均的，所以电场可以施加一个 产生实质性定向的扭矩。 取向 电场被认为是相当不切实际的， 不太对称的分子 双原子的旋转运动， 线性或不对称的顶部分子使偶极子平均化， 一阶矩，所以与电的相互作用 场要弱得多。 赫施巴赫医生已经进行了可行性研究 计算表明，即使在这些情况下， 需要60，000伏/厘米的相对适度的斯塔克场 为了定向线性分子的最低旋转状态， 当它们在分子中冷却到2开氏度时， 梁 赫施巴赫希望验证的这一预测 从实验上讲，这将对整个世界产生巨大的影响 反应动力学领域。 它将提供一个重要的新的 研究碰撞分子中取向效应的能力 光束将是可以实现的， 实验条件