Fig. 2: Raman optical activity (ROA) and 2D ROA mapping of Cys-Se nanorod (NR) film.
From: Enantioselective Se lattices for stable chiroptoelectronic processing media
a Raman spectra of L-Cys-Se NR film and the type of phononic oscillation of atoms. The gray shaded area indicates the first-order Raman peaks at 102 and 143 cm−1, which are attributed to rotational modes about the chain z-axis and the x- or y-axis, respectively. The pink shaded area highlights the Raman peaks at 233 and 237 cm−1, corresponding to the asymmetric and symmetric breathing phonon modes of the lattice structure. The inset shows an enlarged view of the Raman peak region (pink shaded area). b, c incident circular polarization (ICP)-ROA spectra of b first-order, c second-order Raman shift, d ∆-value spectra of levo (L)-, dextro (D)-, racemic (DL)-Cys-Se NR films. The ∆-value, or circular intensity difference (CID), is defined as (IRCP − ILCP)/(IRCP + ILCP) where IRCP and ILCP represent the Raman intensities of right- and left-circularly polarized (RCP and LCP) light, respectively. The raw data are shown as shaded curves, and the smoothed spectra are overlaid as solid lines. e Schematic illustration of the 2D ROA mapping analysis and data analysis. f–h 2D mapping of the normalized ICP-ROA of f L-, g D-, h DL-Cys-Se NRs at the Raman shift peak of 237 cm−1.
