二维红外光谱

文章对二维红外光谱的历史、实验设备、方法原理、具体应用进行了简要的介绍,并对它的前景进行了展望.二维红外光谱是一种通过多束超快（10-15s（1fs）—10-12s（1ps）、中红外（400—4000cm-1）激光对分子的化学键的振动模式进行顺序激发, 从而获得关于分子动态及静态结构信息的方法.它的原理非常类似于二维核磁共振, 但要快上大约6个数量级.现在它已经开始被应用于研究平衡态下快速的分子变化,分子间相互作用（如氢键,偶极-偶极相互作用等）在常温液体里的动态变化, 水氢键网络的演变过程,小分子、多肽和蛋白的静态或瞬间结构变化.     

IR diode laser spectroscopy in molecular beams

A molecular beam spectrometer for recording cold-jet spectra is described. Modulation of the molecular beam is provided by a mechanical chopper. Some results on CO, C₃H₆ and CF₃Cl are presented.     

Time-resolved IR spectroscopy of quantum-optics in semiconductors

Time-resolved IR spectroscopy is a powerful non-destructive technique for probing electron dynamics and plasmonics in semiconductors. We present recent experiments in which intense IR laser pulses are used to induce “quantum-optical” phenomena, including gain without population inversion and slow light, in semiconductor nanostructures. The potential advantages of IR Synchrotron radiation to probe these systems are discussed.     

Photothermal desorption spectroscopy with IR lasers

Medium-energy ion scattering on the relaxed GaAs(110) surface measures a value of 29° ± 3° for the rotation of the top Ga-As atomic chains. Measurements in a scattering geometry especially sensitive to the surface-parallel displacements concomitant with such a bond rotation, show that bond-lengths in the relaxed surface remain unchanged.     

IR spectroscopy of diamondlike silicon-carbon films

IR spectra of metal-containing diamondlike silicon-carbon films are taken for the first time. It is shown that the optical response from the subsystem of free charge carriers in chromium-containing films can be described in terms of a simple model that deals with carriers localized inside clusters several nanometers in size. The data obtained indicate that the electric and dielectric properties of the films can be controlled by technological means during their synthesis and by varying the size, concentration, and conductivity of metallic nanoclusters.     

A study of Fe grown on muscovite with Mössbauer spectroscopy

Mössbauer spectroscopy has been used to study Fe grown on muscovite by thermal evaporation in 10^–6 torr; there is evidence of hcp structure as far as thickness of 7,000 Å; no evidence was found for magnetic ordering. Quadrupole splitting of –0,42 mm/s is attributed to hcp Fe; the resonance lines are broader than that of bcc resonance lines. Results are presented on the isomer shift.     

First experiments on field photodesorption IR spectroscopy

The ion current of adsorbed water molecules is studied experimentally as a function of the frequency of near-IR radiation incident on a surface at frequencies in the intrinsic vibrational bands of the water molecule. The ions are produced by nonequilibrium field surface ionization. The observed band (near one of the combination frequencies) has a width of 100 cm⁻¹ and is shifted relative to the free molecular band by 130 cm⁻¹. Estimates show that the cross section for absorption of the radiation by the adsorbed molecules is 3–4 orders of magnitude larger than for free molecules, as is typical of surface processes. Zh. Tekh. Fiz. 69, 123–127 (September 1999)     

IR spectroscopy of the acetonitrile molecules in porous glasses

The results of investigation of the IR spectra of optical density under the condition of attenuated total internal reflection of acetonitrile in porous glasses with the pores of different radii are presented. It is established that interaction between the acetonitrile molecules and the porous glass matrix with the pores of small dimensions (1.3–4 nm) significantly effects the spectral characteristics of these molecules.     

IR reflection-absorption spectroscopy of CO adsorbed on palladium

Kinetic theory is used to compute the flux and relative translational kinetic energy incident upon a surface oscillating in a rarefied gas. The flux incident upon the oscillatory surface is deficient in low-velocity molecules from the gas during the reentry half of a vibration cycle, in which the surface moves into the gas, because all molecules which are to strike the oscillatory surface from the gas must cross the plane of maximum surface extension during that cycle. The deficiency is largely compensated for by recapture, during the reentry half of a cycle, of low-velocity molecules emitted during the recession half of the cycle. The result of these two opposing effects is that the average energy of gas-surface collisions, and therefore the temperature rise of an oscillatory surface is greater than that of a constant speed plate of the same rms velocity in the same gas. For argon at 300 K and 10^?3 torr incident upon a surface with an rms velocity of 3.3 × 10³ cm sec^?1 the apparent average temperature of incident molecules is 302.91 ° for an oscillatory surface and 302.63 ° for a constant speed plate. Measurements of the temperature rise of an oscillatory surface offer a way to measure thermal accomodation coefficients.     

IR surface plasmon (polariton) phase spectroscopy

New experimental evidence is presented which shows that the reliability and the precision of the determination of the optical constants of the metallic and dielectric surfaces can be improved by using the surface electromagnetic wave absorption spectroscopy and SEW phase spectroscopy simultaneously.