Spectroscopy of vibrational optical activity has been established as a powerful tool to study molecular structures and interactions. In most cases, only fundamental molecular transitions are analyzed. In the present study, we analyze a broader range of vibrational frequencies (40−4000 cm −1 ), which could be measured on a new Raman optical activity (ROA) instrument. An unexpectedly strong vibrational Raman optical activity of 2-chloropropionitrile has been observed within the low-frequency region (40−150 cm −1 ). On the basis of combined molecular dynamics and density functional theory simulations, it could be assigned to intermolecular vibrations. A detailed analysis also revealed connection between spectral shapes and molecular structure and flexibility, such as bending of the CCN group. At the other edge of the scale, within ∼1500−4000 cm −1 , for the first time, many combination and overtone ROA bands have been observed for 2-chloropropionitrile and α-pinene. These were also partially assigned, using quantumchemical computations. The band assignment was confirmed by a comparison with Raman, absorption, and vibrational circular dichroism spectra. The measurement in the broader vibrational range thus significantly extends the information that can be obtained by optical spectroscopy, including intermolecular interactions of chiral molecules and liquids.
In this paper, the effect of heat treatment on the development of nanocrystallites in rapidly quenched
Fe79Mo8Cu1B12
alloy is investigated. The surface morphology is examined using non-contact mode atomic
force microscopy (AFM). The results are compared with those obtained by transmission
Mössbauer spectroscopy (TMS), conversion electron Mössbauer spectrometry (CEMS) and
x-ray diffraction (XRD). It was found that the sample is not fully amorphous even in the
as-quenched state. Minor amounts of bcc-Fe grains were detected on the wheel side of
the ribbon-shaped samples while no indications of the crystalline phase were
observed in the bulk. The crystallization onset is observed after annealing at
410 °C, when bcc-Fe nanograins are quite well developed. More intense crystallization is evidenced
after annealing at higher temperatures, when the content of the crystalline phase increases
progressively. The second crystallization, not discussed in the present paper, is characterized
by the occurrence of additional crystalline phases, and appears after annealing at
650 °C. We suggest a crystallization model assuming no drastic change in the size of the primarily
formed bcc-Fe nanograins with temperature as proved by XRD. The increase in annealing
temperature induces the formation of a higher number of crystalline particles, which form
large irregular agglomerates (80–130 nm in height), in accordance with the AFM data.
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