Hopkins Rebecca J, Howle Chris R, Reid Jonathan P
School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
Phys Chem Chem Phys. 2006 Jun 28;8(24):2879-88. doi: 10.1039/b600530f. Epub 2006 May 24.
We demonstrate that temperature gradients can be investigated in evaporating volatile water/alcohol droplets by characterising the volume averaged temperature by laser induced fluorescence and the near-surface temperature by cavity enhanced Raman scattering. In the former technique, the fluorescence spectrum from Rhodamine B can be used to determine the droplet temperature with an accuracy of +/-1 K. The latter technique uses the band width of the OH stretching Raman band to determine the temperature change within the near-surface volume in which whispering gallery modes propagate with an accuracy of +/-4 K. We demonstrate that the temperatures measured with varying evaporation time, buffer gas pressure, droplet size and composition are consistent with the predictions from a quasi-steady theoretical treatment of the evaporation rate and can be used to investigate temperature gradients within evaporating droplets.
我们证明，通过用激光诱导荧光表征体积平均温度以及用腔增强拉曼散射表征近表面温度，可以研究挥发性水/醇液滴蒸发过程中的温度梯度。在前一种技术中，罗丹明B的荧光光谱可用于以±1 K的精度确定液滴温度。后一种技术利用OH伸缩拉曼带的带宽来确定回音壁模式传播的近表面体积内的温度变化，精度为±4 K。我们证明，在不同蒸发时间、缓冲气体压力、液滴尺寸和组成下测量的温度与蒸发速率的准稳态理论处理的预测结果一致，并且可用于研究蒸发液滴内的温度梯度。
