A. A. Nurmatov

Four-photon polarization spectroscopy of the rotational resonances in liquids in the range 0–3 THz

The spectra of the coherent molecular rotation that coincide with the rotational spectra of the corresponding molecules in the gas phase are measured for the first time using four-photon coherent laser spectroscopy in the range 0–100 cm−1 in several liquids (CCl4, H2O2, D2O, and H2O). The measured spectra make it possible to separate the spectral contributions of the slow rotational molecular motions about the equilibrium and the fast rotations. The selectivity of the action of the microwave radiation on biological objects can be increased using the results obtained.

Spectroscopy of Spontaneous Raman Scattering of a Liquid-Water Local Structure in the Field of an Intense Ultrasound Pulse

A shift of the band envelope of liquid water stretching vibrations in the field of an ultrasonic acoustic pulse is experimentally observed; this shift is indicative of modification of the water cluster structure in the acoustic field. Simple evaluations show that the observed shift can be caused by a change in the average distance between oxygen atoms in a molecular cluster by about 0.05 Å.

Laser-field-induced coherent molecular librations in liquid

The temperature evolution of rotational spectra is demonstrated for four-photon scattering in water in the interval 0.1–8 cm−1 (3–240 THz). A detailed numerical simulation of the spectra is performed. The best agreement is reached using the frequencies of the rotational resonances of free molecules. It is demonstrated that the contribution of coherent librations into the measured signal increases proportionally to the decrease in the shear viscosity of water. The four-photon-scattering spectra of water corresponding to an increase in the temperature and dilution with H2O2 are compared.

Four-photon spectroscopy of coherent molecular rotations in liquids in the 0–3 THz range

The spectra of free, low-frequency (0–3 THz) molecular rotations in liquid CCl4, H2O2, D2O, and H2O, which coincide with the spectra of same molecules in the gas phase, have been observed for the first time by means of four-photon coherent laser spectroscopy. The spectra of water and hydrogen peroxide reveal resonances at the frequencies corresponding to rotational transitions involving the ground vibrational states of the ortho and para spin isomers of water.

Four-photon laser spectroscopy of low-frequency rotational resonances of H2O molecules in the liquid phase

A clearly pronounced structure of the Rayleigh wing consisting of a great number of components is measured in the range 0–100 cm−1 using four-photon polarization spectroscopy. The features observed are compared with the calculated IR spectra of H2O molecules in the gas phase taken from the HITRAN database. A good correlation between the frequency positions of the observed and calculated lines points to the possibility of hindered rotation of water molecules in liquid.

Four-photon laser spectroscopy of liquid water and aqueous solutions of α-chymotrypsin in the range ′5 cm-1

The resonances located at 1.2, 1.6, 2.0, and 2.3 cm−1 with a width of ∼0.2 cm−1 were observed for the first time in the range ±5 cm−1 of the four-photon Rayleigh wing spectra of distilled water and aqueous solutions of the protein α-chymotrypsin. The line at 2.3 cm−1 belongs to the rotational transition 3(2, 1)–4(1, 4) of the ground vibrational state of water. In the presence of the protein, the spectrum is modified by the appearance of new lines, located at 0.74, 2.8, and 3.2 cm−1. The modification of the spectrum observed is interpreted as a manifestation of low-frequency vibrations of large molecular fragments in aqueous protein solutions and as a result of the structuring of water in the vicinity of protein molecules.

Four-photon laser spectroscopy of translational vibrations of a proton in water and hexagonal ice

For the first time, translational vibrations of a proton in H2O, D2O, HDO, and hexagonal ice were found in the Rayleigh line wing using four-photon polarization spectroscopy.

Four-photon polarization spectroscopy of water in a millimeter-wave radiation field

Resonance (frequency 1.4 cm(−1) changes induced in the four-photon optical spectrum of water by a millimeter-wave electromagnetic field are observed experimentally. Comparison with the spectrum of ice in the range 0‒2 cm(1 shows that the action of such a field is of a structure-forming character.

Detection of the structure of the wing of the Rayleigh line in ice, water, and heavy water using four-photon polarization spectroscopy

The spectral structure of the wing of the Rayleigh line in ice, ordinary water (H2O), and heavy water (D2O) is recorded in the frequency range 0–50 cm−1 by means of four-photon polarization spectroscopy. It is shown that this structure can be explained by the collective rotational motion of molecules in cells determined by the structure of hexagonal ice.