Signs of structural changes in molecules in IR spectra with pulsed heating

We have shown that in slow thermal reactions of complex molecules, effects of nonradiative transitions due to quantum beats between resonant states of the combining molecular structures can be observed in conventional (without high time resolution) IR absorption spectra, as oscillations in the intensities of individual lines. We suggest a method to ensure the required level of coherence for the oscillations in an ensemble of molecules, based on application of pulsed heating to the molecular system. Detection of the qualitatively new effects by traditional IR spectroscopy methods, including their quantitative characteristics, considerably increases the information content of the spectral data obtained and makes it possible to use such highly developed experimental methods to study chemical reactions, including the reaction dynamics. The range of these reactions is quite broad, encompassing both “laboratory” and “natural” (geochemistry, ecology, etc.) processes with characteristic times on the order of minutes or more. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 6, pp. 738–743, November–December, 2007.     

苦瓜中维生素C含量的测定

建立苦瓜中维生素C含量直接测定新方法。以10%盐酸溶液为溶剂,采用紫外分光光度法测定含量。维生素C在0—10μg/mL浓度范围内与吸光度呈良好的线性关系,回归方程为：y=0.04746C＋0.00109,r=0.9997。检出限为0.023μg/mL,加标回收率在94.8%—101.1%之间。该法操作简单,干扰离子少,结果准确,测量快速、准确度和灵敏度高,可应用于维生素C含量的测定。     

New model describing interaction between an electromagnetic wave and a molecule

The expediency of refining some basic concepts of the common theory of interaction between an electromagnetic field and a substance using a quasi-classical model for the phenomena of absorption and emission of energy and Raman scattering (RS) is considered. The use of the time-dependent Schrodinger equation for obtaining the transition probability constants is discussed. A new model that describes the intensities of the RS lines and involves the explicit introduction of the perturbation operator for the RS spectrum is proposed. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 3, pp. 309–318, May–June, 2008.