Sum-frequency generation vibrational

Lagutchev A, Hambir SA, Dlott DD. 2007. Nonresonant background suppression in broadband vibrational sum-frequency generation spectroscopy. J Phys Chem C 111 ... 

Lu GQ, Lagutchev A, Dlott DD, Wieckowski A. 2005. Quantitative vibrational sum-frequency generation spectroscopy of thin layer electrochemistry CO on a Pt electrode. Surf Sci 585 3-16. 

Kim et al. [22] have used vibrational sum-frequency generation spectroscopy (SFG) to characterize the surfaces of (3-HMX single crystals, as well as the interface between HMX and the copolymer Estane. SFG is a nonlinear vibrational spectroscopic technique, related to optical parametric amplification that selectively probes vibrational transitions at surfaces and interfaces. Compared with bulk HMX, the surface vibrational features are blueshifted and observed splittings are larger. The technique may have application to detection of explosive residues on surfaces. 

Morkel M, Unterhalt H, Kliiner T, Rupprechter G, Freund H-J (2005) Interpreting intensities in vibrational sum frequency generation (SFG) spectroscopy CO adsorption on Pd surfaces. Surf Sci 586 146... 

Ma, G., Liu, D., and Allen, H.C., Piperidine adsorption on hydrated a-alumina (0001) surface studied by vibrational sum frequency generation spectroscopy, Langmuir, 20, 11620, 2004. 

Because mostly vibrational modes at interfaces are investigated, the method has also been called vibrational sum frequency generation (VSFG). 

More recently, Samec and coworkers investigated the line shape of the fluctuation spectrum at the polarizable water/DCE interface in the presence of the phospholipid DL-a-dipahnitoyl-phosphatidylcholine (DPPC) [32]. The line shape of experimental power spectra similar to those exemplified in Pig. 4.12 b was analyzed in terms of the mean vertical displacement of the interface generated by capillary waves. The experimental results in the presence and absence of DPPC at a wide potential range appear consistent with the description of the liquid/liquid boundary as molecularly sharjf. However it is not entirely clear from this analysis how sensitive the spectmm line shape is to the molecular organization at the liquid/Hquid boundary. As discussed in Section 4.3.2, vibrational sum frequency generation studies of the neat water/DCE interface provide a rather different conclusion. 

Vibrational Sum Frequency Generation (SFG) has provided some of the most detailed pictures of the structure of water at liquid/liquid and liquid/air interfaces [60-64]. In this technique, the overlap of two laser beams at the interfacial region, one visible and one tuneable in the IR region, generates a third beam with a frequency equal to the sum of the two incident beams. The intensity of the generated sum-frequency beam (I (cosf)) is proportional to the intensities of the visible (/(cOyis)) and IR beams (I com))... 

In-situ vibrational spectroscopy has long been used to study the electrified solid/ liquid interface. By using the information given by peak position, width, and lifetime, vibrational spectroscopy can provide the chemical identity of the adsorbate, an estimation of surface coverage, and the orientation and even dynamics of molecules at the electrode. Three different types of vibrational spectroscopy are relevant to the solid/liquid interface. The first two of these, Raman and infrared spectroscopy, are thoroughly discussed in this book. A third technique successfully used to probe the Uquid/soUd electrochemical interface is vibrational sum frequency generation (SFG). SFG was developed as a surface probe some 20 years ago [1], and its use was extended to the electrochemical interface by Tadjeddine over a decade ago [2]. Several reviews examining the use of SFG in non-electrochemical environments exist [3-11]. Tadjeddine wrote two reviews on the application of SFG to electrochemical problems [12, 13). This chapter updates the Tadjeddine work and focuses on the promise and problems of state-of-the-art electrochemical SFG. 

Key words Surfactants - interfaces -vibrational sum frequency generation - monolayers... 

A similar behaviour, as the one from C PyBr, has already been reported for surfactants with a silane head-group adsorbed on smooth silicon surfaces, using FT-IR [34] or vibrational sum-frequency generation [35]. After observing the same relative band ratios for excitation in the visible and in the near infrared spectral range, it can be... 

These findings are consistent with vibrational sum frequency generation experiments [57], which were able to detect methanol at the water surface and suggested that it adsorbs in an ordered layer. In the same stody, however, methyl chloride could not be detected at the surface. Our results also agree with a recent theoretical stody on methyl chloride using a classical polarizable force-field, which showed that despite some preferential orientation with the methyl groups directed towards the water surface, the distribution is rather broad and relatively flat. Other simulations have led to comparable conclusions for MeCl orientation [58, 59]. 

A. Morita, T. Ishiyama, Recent progress in theoretical analysis of vibrational sum frequency generation spectroscopy. PCCP 10(38), 5801-5816 (2008)... 

A. M. Jubb, W. Hua, and H. C. Allen, Annu. Rev. Phy. Chem., 63, 107 (2012). Environmental Chemistry at Vapor/Water Interfaces Insights from Vibrational Sum Frequency Generation Spectroscopy. 

Liu D, Ma G, AUen HC (2005) Adsorption of 4-picoline and piperidine to the hydrated Si02 surface probing the surface acidity with vibrational sum frequency generation spectroscopy. Environ Sci Technol 39(7) 2025-2032. doi 10.1021/es0482280... 

---