Tracking molecular structure deformation of nitrobenzene and its torsion–vibration coupling by intense pumping CARS

Abstract

The structural deformation induced by intense laser field of liquid nitrobenzene (NB) molecule, a typical molecule with restricting internal rotation, is tracked by time-and frequency-resolved coherent anti-Stokes. Raman spectroscopy (CARS) technique with an intense pump laser. The CARS spectra of liquid NB show that the NO 2 torsional mode couples with the NO 2 symmetric stretching mode, and the NB molecule undergoes ultrafast structural deformation with a relaxation time of 265 fs. The frequency of NO 2 torsional mode in liquid NB (42 cm −1 ) at room temperature is found from the sum and difference combination bands involving the NO 2 symmetric stretching mode and torsional mode in time-and frequency-resolved CARS spectra.

Ce–Co-doped BiFeO 3 multiferroic for optoelectronic and photovoltaic applications

“…The intensity enhancement is an indication of spin-dependent scattering mechanism. [25][26][27][28][29] Porporati et al showed that Bi can take part in low wavenumber modes (up to 167 cm −1 ), the oxygen atoms are mainly involved in modes of wavenumber larger than 262 cm −1 , although Fe can participate in modes between 152 cm −1 to 262 cm −1 . [30][31][32][33][34][35] The A 1 (TO 2 ) mode symmetric at 213.5 cm −1 is a soft oxygen mode and is directly associated with the oxygen displacement vector ( ā ā ā).…”

Selective excitation of vibrational modes and probe for asymmetric intramolecular energy redistribution

“…When the C-H stretching vibrational modes 3080 cm −1 and 3050 cm −1 are excited, their frequency difference would appear at 30 cm −1 in the FT power spectra (around zero-time), as shown in figure 2(a). The peak at 70 cm −1 is assigned to the frequency difference between phenyl ring breathing mode v CC ∼1584 cm −1 and NO 2 Another major peak of the FT power spectra is the nitro group torsion mode v torsion ∼48 cm −1 , which originates from the impulsive excitation of femtosecond laser pulses [24]. Owing to the limited spectral detection range, the low-frequency mode v torsion ∼48 cm −1 is invisible in CARS spectra and can only been tracked through FT power spectra.…”

Spin polarization and dispersion effects in emergence of roaming transition state for nitrobenzene isomerization

“…Nitrobenzene is one of the typical energetic materials whose geometries and spectrum properties, isomerization and even dissociation channels have been studied theoretically and experimentally [14][15][16][17][18][19] . Recently, a new reaction channel in the …”

“…Nitrobenzene is one of the typical energetic materials whose geometries and spectrum properties, isomerizations and even dissociation channels have been studied theoretically and experimentally. [14][15][16][17][18][19] Recently, a new reaction channel in the photodissociation process of nitrobenzene was reported, suggesting a unimolecular isomerization process through a typical TS R . [20] So far, most of the previous researches have focused on the dynamic properties of the roaming systems, with certain atoms or functional groups roaming around the rest part and then dissociated or isomerized.…”

“…Nitrobenzene is one of the typical energetic materials whose geometries and spectrum properties, isomerization and even dissociation channels have been studied theoretically and experimentally [14][15][16][17][18][19] . Recently, a new reaction channel in the photodissociation process of nitrobenzene was reported, suggesting a unimolecular isomerization process through a typical TSR [20] .…”