摘要
气体吸收谱线的线宽主要包括碰撞作用引起的洛伦兹线宽和分子热运动引起的高斯线宽,是可调谐二极管激光吸收光谱技术(TDLAS)的重要参数.本项研究在弱吸收条件下,通过对波长调制法中二次与四次谐波峰值比进行理论分析和仿真计算,发现无论洛伦兹和高斯线宽如何变化,二次和四次谐波峰值比具有恒过不动点的特征.本文基于该不动点提出了一种线宽在线测量的方法,并以CO2分子6982.0678 cm-1吸收谱线为例进行实验验证.实验结果表明,该方法可以精确测量线宽,进而根据测量得到的线宽确定气体分压和总压,可有效地提高TDLAS技术在工业现场中的测量精度.
Line width is the key parameter in tunable diode laser absorption spectroscopy （TDLAS）;the dominant line widths are Doppler and collisional broadenings. Under low absorbance, the ratios of 2nd to 4th harmonics at the line center monotonously decrease and intersect at a fixed point, regardless of the changes in Doppler and collisional line widths. Based on this characteristic, a method is proposed which employs the ratios to measure the line width. To validate the reliability and accuracy of the proposed method, the transition of CO2 at 6982.0678 cm^-1 is selected to measure the line width, the gas partial and total pressure. Experimental results show that the proposed method can achieve high precision in actual measurements.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2015年第5期128-132,共5页
Acta Physica Sinica
基金
国家自然科学基金(批准号:51206086
51176085)资助的课题~~
