Transient grating techniques

Rogers JA, Fuchs M, Banet MJ, Hanselman JB, Logan R, Nelson KA. Optical system for rapid materials characterization with the transient grating technique application to nondestructive evaluation of thin films used in microelectronics. Appl Phys Lett 1997 71(2) 225-227. 

Abstract. A recently developed new method to monitor reaction kinetics of intermolecular interaction is reviewed. This method is based on the measurement of the time-dependent diffusion coefficient using the pulsed-laser-induced transient grating technique. Using this method, conformation change, transient association, and transient dissociation on reactions are successfully detected. The principle and some applications to studies on changes in the intermolecular interactions of photosensor proteins (e.g., photoactive yellow protein, phototropins, AppA) in the time domain are described. In particular, unique features of this time-dependent diffusion coefficient method are discussed. 

Frez C, Diebold GJ, Tran C et al. (2006) Determination of thermal diffusivities, thermal conductivities, and sound speeds of room temperature ionic liquids by the transient grating technique. J Chem Eng Data 51 1250-1255... 

Abstract In this paper we address two aspects of ionic liquids (ILs) that to date have either no or limited studies. They are (1) exploitation of unique features of ILs to develop novel spectroscopic methods which otherwise is not possible and (2) development of novel spectroscopic methods for the sensitive and accurate determination of thermal physical properties of ILs. In the first category, we have successfully developed a novel, highly sensitive and accurate method for the determination of enantiomeric compositions of chiral compounds with different sizes, shape and functional groups including pharmaceutical products. This method is based on the use of a chiral IL which serves both as a solvent and also as a chiral selector. We have also demonstrated that ILs can be used to substantially enhance the sensitivity of thermal lens measurements. In the second category, we have demonstrated that transient grating technique and thermal lens technique can be used for the sensitive, accurate, nondestructive determination of thermal physical properties of ILs. 

DETERMINATION OF THERMAL PHYSICAL PROPERTIES OF IONIC LIQUIDS BY TRANSIENT GRATING TECHNIQUE... 

Theoretical treatment of photoacoustics and its application to the transient grating technique have been reported previously." The photoacoustic... 

TABLE 5. Themial Diffusivities (a). Sounds Speeds (c) and Damping Parameter (a) Determined by Transient Grating Technique Together with Some Reported Values. 

In summary, it has been demonstrated that the transient grating technique can be used to determine thennal physical properties (thermal diffusivity and thermal conductivity) of ILs. The technique has relatively high precision, namely relative errors are about 1%. It also has relatively high accuracy thermal conductivity values of ILs determined by this method agree, within 1% with values previously determined by other workers. More importantly. 

In experiments currently in progress, the techniques used in this paper are being applied to the observation of local polymer dynamics in concentrated solutions and in the bulk. Measurements can be made on time scales as long as several triplet lifetimes ( 100 msec) because the transient grating technique utilizes absorption and not fluorescence. This long time window will allow the investigation of local motions in the bulk as a function of temperature from the rubbery state to the glass transition. 

Terazima, M., Hirota, N. Measurement of the quantum yield of triplet formation and short triplet lifetimes by the transient grating technique. J. Chem. Phys. 95, 6490-6495 (1991)... 

M. Amirkhani, A. Taschin, R. Cucini, P. Bartolini, D. Leporini and R. Torre, Polymer thermal and acoustic properties using heterodyne detected transient grating technique. Journal of Polymer Science B, Vol. 49, 2011, pp. 685-690. 

In 1978, Salcedo, et al at Stanford University reported the measurement of singlet electronic excitation transport in a molecular crystal. The time scale of their measurement was 1 ns. Also in 1978, the first reports were published of the measurement of mass transport by transient grating techniques. Hervet, et al of the College de France reported the translational diffusion coefficient of the photochromic dye methyl red in an aligned liquid crystal, as a function of direction. The time scale was 0.1 s. Smith and McConnell at Stanford University used Fluorescence Redistribution After Pattern Photobleaching to measure the diffusion coefficient of dye-labeled phospholipid in oriented multibilayer films. The time scale was 100 s. 

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