Opacity of H- at High Density

白色矮星是质量与太阳相似的恒星演化的最终产物。有氢大气层的老白色矮星有高密度和低温的光球。决定其光谱外观的不透明度的主要来源是负氢离子、氢分子的碰撞诱导吸收以及氢原子和分子的瑞利散射。在理论上预测这些白色矮星的颜色时，最大的不确定性来源是高密度下负氢离子的不透明性。 这种不透明度以前没有被精确计算的物质密度大于0.001克每立方厘米，一个政权，其中相邻的粒子扰动离子的束缚态结构。该项目研究碰撞如何改变负氢束缚态的性质，包括其结合能、配分函数、热力学丰度以及束缚-自由和自由-自由截面。项目负责人将计算高密度下该离子的不透明度。该研究计划将教育和培训个人应用基础物理学解决复杂问题。参与者包括刚刚开始科学职业生涯的学生，以及将技能扩展到新领域的经验丰富的个人。培训将有助于培养一批精通科学、对技术先进的社会具有普遍效用的个人。在K-12级的外展计划中，项目主任将与两个科学博物馆（科学中心和地球博物馆）合作，并就我们对太阳和其他恒星的基本可观察特征（大小，亮度，颜色）的现代科学理解的主题进行互动讨论。将在相关的基本微物理过程（核、原子和分子，包括研究方案的主题）与太阳的可观测特性之间建立直接联系。

White dwarfs are the end product of stellar evolution for stars of mass similar to the Sun. Old white dwarfs with hydrogen atmospheres have photospheres with high densities and low temperatures. The dominant sources of opacity determining their spectral appearance are the negative hydrogen ion, collision induced absorption of the hydrogen molecule, and Rayleigh scattering of hydrogen atoms and molecules. The greatest source of uncertainty in the theoretical prediction of the colors of these white dwarfs is the opacity of the negative hydrogen ion at high density. This opacity has not previously been calculated accurately for matter densities greater then 0.001 grams per cubic centimeter, a regime in which neighboring particles perturb the ion's bound state structure. This project is a study of how collisions modify the properties of the negative hydrogen bound state, including its binding energy, its partition function, its thermodynamic abundance, and its bound-free and free-free cross sections. The project director will calculate the opacity of this ion at high densities.Broader Impact. The research program will educate and train individuals in the application of basic physics to complex problems. The participants include students just starting a career in science, as well as individuals with more experience who will extend their skills to new areas. The training will contribute to the development of a proficient, scientifically informed group of individuals of general utility to a technologically advanced society. In an outreach program for levels K-12, the project director will partner with two science museums (the Science Center and the Museum of the Earth) and present interactive discussions on the topic of our modern scientific understanding of the basic observable features (size, brightness, color) of the Sun and other stars. A direct connection will be made between relevant fundamental microphysical processes (nuclear, atomic and molecular, including those that are the subject of the research program) and the observable properties of the Sun.