Infrared absorption and resonance Raman scattering of photochromic triphenylformazans

1983 ◽  
Vol 61 (5) ◽  
pp. 809-816 ◽  
Author(s):  
J. W. Lewis ◽  
C. Sandorfy
Keyword(s):  
Excited State ◽  
Raman Scattering ◽  
Proton Transfer ◽  
Raman Spectra ◽  
Infrared Absorption ◽  
Resonance Raman ◽  
Tautomeric Equilibrium ◽  
Resonance Raman Scattering ◽  
Excited State Proton Transfer ◽  
Resonance Raman Spectra

The infrared and resonance Raman spectra of the two long-lived forms of triphenylformazan and several of its derivatives have been examined. The spectra of unsymmetrically 15N-labelled derivatives suggest that two tautomers exist for each of the two forms. This observation is confirmed by the spectra of 1-(p-halophenyl)-3,5-diphenylformazans. The spectra of the non-chelate forms of these latter compounds demonstrate that the position of the tautomeric equilibrium is influenced by the electron-attracting ability of the para-halo-substituent. A comparison of the resonance Raman spectra of the two forms leads to the conclusion that excited state proton transfer is the initial photoevent in the photochromism of the triphenylformazans.

Resonance Raman Scattering from Single Levitated Microparticles

2002 ◽  
Vol 56 (11) ◽  
pp. 1436-1443 ◽  
Author(s):  
Mary L. Laucks ◽  
Feng Zheng ◽  
E. James Davis
Keyword(s):  
Raman Scattering ◽  
Raman Spectra ◽  
Morphological Variability ◽  
Resonance Raman ◽  
Deformation Mode ◽  
Potassium Nitrate ◽  
Laser Wavelength ◽  
Resonance Raman Scattering ◽  
Stretch Mode ◽  
Resonance Raman Spectra

Measurements of resonance Raman scattering from single crystalline (or amorphous) particles suspended in an electrodynamic balance have been made for inorganic and organic microparticles, potassium permanganate (KMnO4) and p-nitrosodimethylaniline ( p-NDMA), respectively. The microparticle dimensions were in the range 10–50 μm. The particles were obtained by evaporating aqueous solution droplets of KMnO4 and p-NDMA (0.01 M concentration) and potassium nitrate or sodium nitrate (1.0 M concentration) added as a nonresonance Raman standard or reference. Resonance Raman spectra were obtained using laser illumination at wavelengths of 514.5 and 488.0 nm. For MnO−4 particles at a laser wavelength of 514.5 nm, the fundamental symmetric stretch mode (ν1) and up to four overtones were observed. In addition, the antisymmetric stretch mode (ν3) and the combination mode (ν1 + ν3) could be seen. In p-NDMA particles, the phenyl-nitroso deformation mode (ν1) and the symmetric benzene ring-stretching mode (ν3) were observed using 488.0 nm laser radiation, but no overtones were distinguishable. As a measure of the morphological variability between particles, the ratio of the intensity of ν1 to the intensity of the largest nitrate ion (Raman) peak (normalized by the concentrations) was determined for each spectrum. This enhancement ratio or reference ratio was of order 100 and varied by 27% for 12 KMnO4 particles with 514.5 nm illumination, by 39% for 10 KMnO4 particles at 488.0 nm, and by 16% for 14 p-NDMA particles at 488.0 nm. Resonance Raman spectra obtained for KMnO4 particles before and after deliquescence indicated that photolysis occurred in the presence of water.

Comment on “Sensitive marker bands for the detection of spin states of heme in surface-enhanced resonance Raman scattering spectra of metmyoglobin” by Y. Kitahama, M. Egashira, T. Suzuki, I. Tanabe and Y. Ozaki

The Analyst ◽  
2015 ◽  
Vol 140 (17) ◽  
pp. 6145-6146 ◽  
Author(s):  
A. Feis ◽  
G. Smulevich
Keyword(s):  
Silver Nanoparticles ◽  
Raman Scattering ◽  
Resonance Raman ◽  
Spin States ◽  
Resonance Raman Scattering ◽  
Surface Enhanced ◽  
Scattering Spectra ◽  
Resonance Raman Spectra ◽  
Raman Scattering Spectra ◽  
Sensitive Marker

We contrast recently reported surface-enhanced resonance Raman spectra (SERRS) of myoglobin on silver nanoparticles with established knowledge about this complex.

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