EFFECTS OF FREE ELECTRON LASER FAR INFRARED RADIATION ON LARGE BIOMOLECULES

该计划的主要目标是实现前所未有的解决方案 在DNA和其它生物分子远红外（FIR）透射研究中 利用罗格斯自由电子的独特时间依赖性的物种 激光（FEL）。 这项研究计划的最终目标是证明 远红外辐射增强生化活性。 一个重要 第一步是通过实验确定是否存在定义明确的FIR DNA等生物学重要分子中的活跃集体模式。 这些模式的自然线宽是否比它们的 频率将被确定。 低频、大振幅、集体 DNA中涉及大量原子的模式被认为是 重要的是允许DNA双螺旋结构的转变 这是复制和转录等过程所必需的。 到 用傅里叶变换光谱仪对取向薄膜进行远红外研究 已经显示出宽的吸收带， 可能的碱基对的统计分布， 结构周期性沿着螺旋轴。 光子回波技术， 罗格斯大学的自由电子激光将被应用于获得显着改善 DNA的FIR光谱的分辨率。 术语“光子回波”表示 原子系统自发发出的光脉冲 先前由两个相干光脉冲照射，并在 第二个脉冲后的时间几乎等于两个脉冲之间的时间 激励脉冲

The major objective of this program is to achieve unprecedented resolution in far-infrared (FIR) transmission studies of DNA and other biomolecular species utilizing the unique time dependence of the Rutgers' free electron laser (FEL). The ultimate goal of this research program is to demonstrate the enhancement of biochemical activity with FIR radiation. An important first step is to experimentally determine the existence of well defined FIR active collective modes in biologically important molecules such as DNA. Whether the natural line widths of these modes are small compared to their frequencies will be determined. Low frequency, large amplitude, collective modes in DNA involving large numbers of atoms have been proposed to be important in allowing the structural transitions in the DNA double helix that are required for processes such as replication and transcription. To date, FIR studies of oriented films using fourier-transform spectrometers have shown broad absorption bands which are inhomogeneously broadened due to the statistical distribution of the possible base pairs and imperfect structural periodicity along the helix axis. Photon echo techniques using the Rutgers' FEL will be applied to obtain significantly improved resolution for the FIR spectra of DNA. The term "photon echo" denotes the pulse of light which is emitted spontaneously from a system of atoms previously irradiated by two coherent light pulses and is observed at a time after the second pulse very nearly equal to the time between the two excitation pulses.