A Comparative Study of the CD and CH Stretching Spectral Regions of Typical Surfactants Systems Using VSFS: Orientation Analysis of the Terminal CH₃ and CD₃ Groups

Abstract

ARTICLEmonolayer of dodecanol is used to explore the limitations and advantages of performing an orientational analysis of the terminal methyl in the CD region.

Amide III SFG Signals as a Sensitive Probe of Protein Folding at Cell Membrane Surface

“…In Figure 7, before adding the pardaxin into the lipid bilayer, the spectra show two narrow peaks at 2105 and 2175 cm -1 , which are assigned to CD 2 symmetric stretch (CD 2, ss) and CD 2 Fermi resonance (CD 2,FR ). [58][59][60] Following the injection of the pardaxin molecules, the bilayer is perturbed and the spectra are dominated by the peaks at 2065, 2100, 2125 and 2225 cm -1 . These peaks are contributed to the CD 3 symmetric stretch (CD 3, ss), CD 2 symmetric stretch (CD 2, ss), CD 3 Fermi resonance (CD 3,FR ), and CD 3 asymmetric stretch (CD 3, as), respectively.…”

“…These peaks are contributed to the CD 3 symmetric stretch (CD 3, ss), CD 2 symmetric stretch (CD 2, ss), CD 3 Fermi resonance (CD 3,FR ), and CD 3 asymmetric stretch (CD 3, as), respectively. [58][59][60] In addition to these peaks, a broad band in the right tails of the 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 spectra is observed before 200 min, which comes from the background of water. 60 After 200 min, the spectra are dominated by the peaks at 2070, 2105, 2125, 2180 and 2210 cm -1 , which are originated from the CD 3 symmetric stretch (CD 3, ss), CD 2 symmetric stretch (CD 2, ss), CD 3 Fermi resonance (CD 3,FR ), CD 2 Fermi resonance (CD 2,FR ), and CD 3 asymmetric stretch (CD 3, as), respectively.…”

“…60 After 200 min, the spectra are dominated by the peaks at 2070, 2105, 2125, 2180 and 2210 cm -1 , which are originated from the CD 3 symmetric stretch (CD 3, ss), CD 2 symmetric stretch (CD 2, ss), CD 3 Fermi resonance (CD 3,FR ), CD 2 Fermi resonance (CD 2,FR ), and CD 3 asymmetric stretch (CD 3, as), respectively. [58][59][60] It is worth noting that the SFG spectra undergo two striking changes after 200 min: 1) the broad band in the right tails of the spectra disappears; 2) the phase signs for the nonresonant background and CD 3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 …”

Vacuum ultraviolet photolysis of hydrogenated amorphous carbons

“…The asymmetric features from CD 3 and CD 2 are located at about 2220 and 2200 cm −1 , while the symmetric modes are located at 2073 cm −1 and 2100 cm −1 (e.g., Tyrode & Hedberg 2011).…”

Photocatalytic oxidation of the organic monolayers on TiO2 surface investigated by in-situ sum frequency generation spectroscopy

“…30,31 As already discussed, the vibration modes of the CH 2 group in a long alkyl chain with an all-trans conformation are SFG-inactive due to the centrosymmetric structure; thus, the SFG peaks observed for the CH 2 group cannot be used to evaluate its population but mainly used to characterize the number of the gauche defects in the long alkyl chains. 39,40 The conformational gauche defects break the all-trans structure of the alkyl chain and reflect the disordering of the monolayer. Thus, the weak SFG intensity of CH 2 compared to that of CH 3 in Fig.…”