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By using CCSD(T) and EOM-CCSD methods together with quasirelativistic energy-consistent small-core pseudopotentials and large atom-centered basis sets as well as bond functions, the potential energy curves (PECs) for the ground state and several low-lying singlet excited states of the van der Waals molecular systems between cadmium atom interacting with RG atoms (RG = He, Ne, Ar, Kr, Xe and Rn) are obtained. The dispersion coefficients of ground state for Cd-RG have been computed. And the spectroscopic constants of the bound states of Cd-RG molecules have been calculated, the spectroscopic constants of ground state and C1Π state of Cd-RG complexes are in reasonable agreement with the available theoretical and experimental results; the vertical excitation energies of singlet low-lying excited states are also obtained. And the transition dipole moments (TDMs) of (3)1Σ+-X1Σ+ and (4)1Σ+-X1Σ+ transitions are discussed, which would be helpful to understand the transition properties of Cd-RG complex. Furthermore, frequencies of vibrational transitions, rotational constants, Franck-Condon factors (FCFs) of C1Π-X1Σ+ transition and oscillator strengths of Cd-RG have also been acquired. The present work would be of value to understand on the electronically excited states of Cd-RG molecule, especially the electronic structure and spectroscopic characteristics of the singlet excited states.

Polarization is a property of vector beam that is widely used in many areas of science and technology. And vector beam is also called polarization vortex beam. Radially polarized beam and azimuthally polarized beam are the paradigm of vector beam. Extreme ultraviolet (EUV) vector beam could be applied in many fields such as diffractive imaging, Extreme Ultraviolet Lithography (EUVL), or ultrafast control of magnetic properties. In our experiments, a home-made EUV spectrometer was used to generate a tunable ultrafast EUV coherent light source based on high-order harmonic generation (HHG) by intense femtosecond laser. The apparatus features by using the plane grating in conical diffraction. The radially polarized vector beam and Gaussian beam with 800 nm, 35 fs laser pulses were applied to interact with Argon atoms, respectively. The high harmonic spectrums with a polarization singularity and a Gaussian distribution were observed. The experimental results demonstrate that the EUV vector beam could be transfered from near-infrared driven laser during the highly nonlinear interaction. The short-wavelength radiation with a polarization singularity can reach a photon flux of 108 per second. And the harmonic orders produced by Gaussian beam are significantly higher than that of vector field. The mechanism of macroscopic phase matching was discussed. It indicates that the phase matching for vector harmonic yields is similar with that driven by a Gaussian beam. In this case, EUV vector beam through HHG has been obtained, which provides one important method for attosecond vector pulses and opens new possibilities for exploring and manipulating the time-dependent evolution of quantum states in atom and molecule.

Reaction conditions were optimized to increase the content of resistant starch in adlay starch using esterification with glutaric acid, and the physicochemical properties of the prepared glutarate starches were investigated. Different amounts of glutaric acid (0.1-0.5 g/g starch, dry weight basis) were reacted with adlay starch at various temperatures (70-130 °C) and reaction times (3-9 h). The resistant starch levels increased with increased glutaric acid content, reaction temperature, and reaction time. The color difference was mainly affected by reaction time. The highest resistant starch content (RS 66%) was obtained using conditions of 0.4 g glutaric acid/g starch, 115 °C, and 7.5 h, with a color difference of 10.24. After digestion with α-amylase and amyloglucosidase, the water-soluble fraction of glutarate starch had more oligosaccharides than high-amylose maize starch (RS 43%). FT-IR and solid-state NMR detected carbonyl groups in the glutarate starch, indicating the formation of cross-linkages through esterification. The granular structure of the glutarate starches was not destroyed and they retained birefringence. After heating with an excess of water, the granules kept their shape but lost their birefringence. The glutarate starches had low solubility in both cold and hot water, and the resistant starch contents were unchanged after heating due to the restriction of swelling by cross-linking. The glutarate starches had a similar chain-length distribution to raw starch, indicating that acid hydrolysis took place at branching points in the amorphous region. Furthermore, the glutarate starches possessed a weaker crystalline region, more diverse double helical chains, and lower enthalpy than raw starch.

Femtosecond laser-induced dissociation and Coulomb explosion of polyatomic molecule C2H6 were systematically investigated using a time-of-flight mass spectrometer and a chirped pulse amplifier laser. With the laser intensity varying from 2.4×1015 W/cm2 to 1.2×1016W/cm2, strong molecular ions C2Hn+ (n=0–6) and atomic ions Cm+ (m=1–3) signals were observed. The double-peak structure of atomic ions indicated the occurrence of Coulomb explosion. Compared with the nearly isotropic distribution of C+, highly charged ions Cm+ (m=2–3) exhibited a sharply anisotropic angular distribution, which was attributed to the geometric alignment.

The kinetic energy release of fragment ions produced by the interaction of femtosecond laser pulse radiation with diatomic and linear triatomic molecules N2, CO, CO2 and CS2 is investigated. In the case of linear polarization, angles at which the kinetic energy release of ions has the maximum value are different from the alignment of molecules though the kinetic energy release of fragment atomic ions depends on the angle between the laser polarization vector and the detection axis of the time-of-flight. For the diatomic molecules, the critical internuclear distance in multielectron dissociative ionization with a circularly polarized light is larger than that with a linearly polarized light. For linear triatomic molecules, our data indicate that a concerted Coulomb explosion process is a universal phenomenon in the interaction of molecules with intense laser fields, even in the circularly polarized regime. During two C–O (or C–S) bonds breaking simultaneously, the C ion obtained larger energy in circular polarization than that in the linear polarization. Different variations of kinetic energy release between the diatomic and the linear triatomic molecules are discussed.

The SMART model (Simulation Model for Acidification's Regional Trends) was developed to estimate long-term chemical changes in soil and lake water in response to changes in atmospheric deposition. Its major outputs include base saturation, pH, and the molar Al/Ca ratio for soils, and major cations and anions for soil and lake water. The model structure is based on the anion mobility concept and the charge balance principle. SMART was applied to the Christmas Lakes, a chain of small oligotrophic catchments in northeast subarctic Finnish Lapland (69°25′N, 29°11′E), located close to the border with Norway and 40 km from the Nikel smelter in Russia, a major source of sulfur emissions. The Christmas Lakes are less than 60 ha in size, have clear water, and are low in base cations and alkalinity. At present, the lakes are not very acidic, the pH being around 6.5 in autumn. The SMART model was calibrated to present soil and water quality data, using best estimates for historical deposition patterns for the period 1890–1990. The model applications in this paper are intended to demonstrate the range of potential catchment responses in northern Lapland for different assumptions concerning sulfur. The two calibrations of the model, assuming (1) a high sulfur deposition in combination with sulfate adsorption and (2) a lower present deposition with no adsorption, revealed that the present sulfur deposition has to lie between 0.4 and 0.8 g S/m2/year. The model results for both calibrations indicate that future sulfur deposition would have to be very low to stop and reverse the ongoing acidification. However, since the present base saturation is fairly high (>50%), there is still time (several years) to reduce the sulfur deposition to values the system can tolerate.

Laser-induced Coulomb explosion of CO is studied experimentally using differently polarized femtosecond laser pulses of 2×1015 W/cm2 intensity at λ = 800 nm. The channels of molecular Coulomb explosion are observed to be independent of the laser polarizations. The critical distance R is deduced to be larger for the circularly polarized light in comparison with the linearly polarized light. The initial emissions of C+, C2+, O+, and O2+ ions are anisotropic for linear polarization and isotropic for circular polarization. The suppression of ionization occurs for the elliptically and circularly polarized lasers.

Ionization and dissociation of linear triatomic molecules, carbon dioxide, are studied in 50-fs 800-nm strong laser fields using time-of-flight mass spectrometer. The yields of double charged ions and various fragment ions (CO+, On+, and Cn+ (n = 1, 2)) are measured as a function of ellipticity of laser polarization in the intensity range from 5.0 × 1013 W/cm2 to 6.0 × 1014 W/cm2. The results demonstrate that non-sequential double ionization, which is induced by laser-driven electron recollision, dominates double ionization of CO2 in the strong IR laser field with intensity lower than 2.0 × 1014 W/cm2. The electron recollision could also have contribution in strong-field multiple ionization and formation of fragments of CO2 molecules. The present study indicates that the intensity and ellipticity dependence of ions yields can be used to probe the complex dynamics of strong-field ionization/dissociation of polyatomic molecules.