STARK HOLE BURNING SPECTROSCOPY OF MODEL HEMES

HEME 模型的 STARK 孔燃烧光谱

• 批准号: 3777999
• 负责人: JOHN R LOMBARDI
• 金额: --
• 依托单位: CITY COLLEGE OF NEW YORK
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3777999
• 关键词: crystallization; dipole moment; electric field; electronic spectra; heme; lasers; metalloporphyrins; molecular dynamics; optical polarization; porphyrins

The research described in this proposal is a continuation of a study of biologically important molecules in the solid state, with respect to their electronic excited state properties, photochemistry and dynamics, using a combination of optical hole-burning and the Stark effect. When an absorbing molecule is dissolved in a matrix, its electronic spectrum is inhomogeneously broadened due to variations in the local environments. If a laser which has a bandwidth much less than the inhomogeneous band width is used to excite these absorbers, it is possible to burn an optical hole in the spectrum. Holes result from photochemistry, transient storage or molecular reorientation. Since the hole widths are often measured in MHz, when coupled with the Stark effect, this becomes a very high resolution probe of molecular properties. The long-term objectives of this research are to extract detailed excited state information (e.g. dipole moments, polarizabilities, geometry) from isolated porphyrin molecules using Stark hole-burning method and develop and extend the techniques so that it can be used as a high resolution probe on biological molecules in more physiologically realistic environments. Specifically we intend to continue our study of simple free base and metalloporphyrins in well defined n-alkane crystal matrices. Then the study will be extended to use randomly oriented porphyrins in glasses. Finally, we will apply Stark hole-burning to more complex biological molecules (e.g. heme) in low temperature glasses and solutions. The methodology involves the growth of single mixed (porphyrin/n-alkane) crystals and making low temperature glass solutions. The sample is placed between electrodes and immersed in liquid N2 or He and an absorption or emission spectrum obtained. Optical holes are burned and scanned with a narrow band laser; the Stark field is applied either DC or pulsed depending on the need. The subsequent electric field effects are then related to molecular excited state properties and dynamics.

本提案中描述的研究是以下研究的继续 固态中具有重要生物学意义的分子，涉及 它们的电子激发态性质，光化学和动力学， 使用光学烧孔和斯塔克效应的组合。什么时候 吸收分子溶解在基质中，它的电子光谱 由于当地环境的变化而不均匀地扩大。 如果一个激光的带宽远远小于非均匀频带 宽度被用来激励这些吸收体，则有可能燃烧 光谱中的光学空穴。小孔是由光化学作用造成的， 瞬时存储或分子重定向。因为孔的宽度是 通常以兆赫为单位测量，再加上斯塔克效应，这就变成了 一种非常高分辨率的分子性质探针。 这项研究的长期目标是提取详细的兴奋 状态信息(例如偶极矩、极化率、几何形状) 斯塔克烧孔法分离卟啉分子及其研究进展 并对技术进行扩展，以便将其用作高分辨率 更具生理学真实感的生物分子探索 环境。具体地说，我们打算继续研究Simple 正构烷烃晶体中的游离碱和金属卟啉 矩阵。然后将研究扩展到使用随机定向 玻璃杯里的卟啉。最后，我们将把Stark烧洞应用到更多 低温玻璃中的复杂生物分子(例如，血红素)和 解决办法。 该方法涉及单一混合(卟啉/正构烷烃)的生长。 结晶和制造低温玻璃溶液。样品是 放置在电极之间，并浸入液态氮气或He和An 获得吸收光谱或发射光谱。光学孔洞被烧毁， 用窄带激光扫描；斯塔克场应用于DC 或根据需要进行脉冲治疗。随后的电场效应 然后与分子激发态的性质和动力学有关。