The Raman and infrared spectra of all-trans-astaxanthin (AXT) in dimethyl sulfoxide (DMSO) solvent were investigated experimentally and theoretically. Density functional cal-culations of the Raman spectra predict ...The Raman and infrared spectra of all-trans-astaxanthin (AXT) in dimethyl sulfoxide (DMSO) solvent were investigated experimentally and theoretically. Density functional cal-culations of the Raman spectra predict the splitting of the υ1 band into υ1-1 and υ1-2 compo-nents. The absence of splitting in Raman experimental spectra is ascribed to the competition between the two symmetric C=C stretching vibrations of the backbone chain. The υ1 band is very sensitive to the excitation wavelength: resonance excitation stimulates the higher-frequency υ1-2 mode, and off-resonance excitation corresponds to the lower-frequency υ1-1 mode. Analyses of the intramolecular hydrogen bonding between C=O and O-H in the AXT/DMSO system reveal that the C4=O1...H1-O3 and C4'=O2...H2-O4 bonds are strengthened and weakened, respectively, in the electronically excited state compared with those in the ground state. This result reveals significant variations of the AXT molecular structure in different electronic states.展开更多
We report the preparation of D2 molecules in v=2 level in molecular beam condition. A single longitudinal mode laser system was used for excitation of D2 from (v=0, j=0) to (v=2, j=0) with the scheme of stimulated...We report the preparation of D2 molecules in v=2 level in molecular beam condition. A single longitudinal mode laser system was used for excitation of D2 from (v=0, j=0) to (v=2, j=0) with the scheme of stimulated Raman pumping. An excitation efficiency of 25.2% has been achieved, which was determined by the scheme of resonance-enhanced multiphoton ion- ization. Dependence of relative excitation efficiency on laser energy has been measured. We found that the increasing rate of excitation efficiency became slower as pulse energy of Stokes laser increase, while the excitation efficiency still increases approximately linearly with pump pulse energies up to 60 mJ. The spectral line shapes of Raman transition was also measured at different laser energies and considerable dynamical Stark effect was observed. A single peak was found on the three dimension surface of relative excitation efficiency, indicating the process occurred in the present study is a process of stimulated Raman pumping instead of stimulated adiabatic Raman passage.展开更多
We study the H+CH4/CD4-+H2/HD+CH3/CD3 reactions using the time sliced velocity map ion imaging technique. Ion images of the CH3/CD3 products were measured by the (2+1) resonance enhanced multi-photon ionization ...We study the H+CH4/CD4-+H2/HD+CH3/CD3 reactions using the time sliced velocity map ion imaging technique. Ion images of the CH3/CD3 products were measured by the (2+1) resonance enhanced multi-photon ionization (REMPI) detection method. Besides the CH3/CD3 products in the ground state, ion images of the vibrationally excited CH3/CD3 products were also observed at two collision energies of 0.72 and 1.06 eV. It is shown that the angular distribution of the products CH3/CD3 in vibrationally excited states gradually vary from backward scattering to sideways scattering as the collision energy increases. Compared to the CH3/CD3 products in the ground state, the CH3/CD3 products in vibrationally excited states tend to be more sideways scattered, indicating that larger impact parameters play a more important role in the vibrationally excited product channels.展开更多
Preparation of a high flux of hydrogen molecules in a specific vibrationally excited state is the major prerequisite and challenge in scattering experiments that use vibrationally excited hydrogen molecules as the tar...Preparation of a high flux of hydrogen molecules in a specific vibrationally excited state is the major prerequisite and challenge in scattering experiments that use vibrationally excited hydrogen molecules as the target. The widely used scheme of stimulated Raman pumping suffers from coherent population return which severely limits the excitation efficiency. Re- cently we successfully transferred D2 molecules in the molecular beam from (v=0, J=0) to (v=1, J=0) level, with the scheme of Stark-induced adiabatic Raman passage. As high as 75% of the excitation efficiency was achieved. This excitation technique promise to be a unique tool for crossed beam and beam-surface scattering experiments which aim to reveal the role of vibrational excitation of hydrogen molecules in the chemical reaction.展开更多
It is theoretically shown that excitonic Doppler-Rabi oscillations can occur in an organic slab moving along the axis of a high-Q cavity. Due to the N enhancement of the vacuum Rabi frequency, this effect can be more ...It is theoretically shown that excitonic Doppler-Rabi oscillations can occur in an organic slab moving along the axis of a high-Q cavity. Due to the N enhancement of the vacuum Rabi frequency, this effect can be more eas ily observed than that in a moving two-level atom.展开更多
The reaction dynamics of the fluorine atom with vibrationally excited D2(v=1, v=0) was investigated using the crossed beam method. The scheme of stimulated Raman pumping was employed for preparation of vibrationally e...The reaction dynamics of the fluorine atom with vibrationally excited D2(v=1, v=0) was investigated using the crossed beam method. The scheme of stimulated Raman pumping was employed for preparation of vibrationally excited D2 molecules. Contribution from the reaction of spin-orbit excited F*(2P1/2) with vibrationally excited D2 was not found. Reaction of spin-orbit ground F(2P3/2) with vibrationally excited D2 was measured and DF products populated in v'=2, 3, 4, 5 were observed. Compared with the vibrationally ground reaction, DF products from the vibrationally excited reaction of F(2P3/2)+D2(v=1, j=0) are rotationally “hotter”. Differential cross sections at four collision energies, ranging from 0.32 kcal/mol to 2.62 kcal/mol, were obtained. Backward scattering dominates for DF products in all vibrational levels at the lowest collision energy of 0.32 kcal/mol. As the collision energy increases, angular distribution of DF products gradually shifts from backward to sideway. The collision-energy dependence of differential cross section of DF(v’=5) at forward direction was also measured. Forward-scattered signal of DF(v'=5) appears at the collision energy of 1.0 kcal/mol, and becomes dominated at 2.62 kcal/mol.展开更多
In this paper, a procedure is proposed for measuring Wigner characteristic function for motion of a single trapped ion. In the scheme, the trapped ion is driven by two laser beams with different frequencies tuned to t...In this paper, a procedure is proposed for measuring Wigner characteristic function for motion of a single trapped ion. In the scheme, the trapped ion is driven by two laser beams with different frequencies tuned to the first lower and upper vibrational sidebands, respectively. Unlike other previous scheme, our scheme does not require the displacement of the external state before the ion-laser interaction and thus our scheme night be more simple and feasible. The scheme can also be used to prepare the motional Schroedinger cat states and entangled coherent states.展开更多
In this paper, we propose a scheme for generating an arbitrary three-dimensional pure state of vibrational motion of a trapped ion. Our scheme is based on a sequence of laser pulses, which are tuned to the appropriate...In this paper, we propose a scheme for generating an arbitrary three-dimensional pure state of vibrational motion of a trapped ion. Our scheme is based on a sequence of laser pulses, which are tuned to the appropriate vibrational sidebands with respect to the appropriate electronic transition.展开更多
We propose a scheme for the generation of entangled coherent states for the center-of-mass and relative vibrational modes of two trapped ions. In the scheme the ions are simultaneously illuminated by a single standing...We propose a scheme for the generation of entangled coherent states for the center-of-mass and relative vibrational modes of two trapped ions. In the scheme the ions are simultaneously illuminated by a single standing-wave laser tuned to the carrier. The scheme allows the production of an entangled coherent states with a considerably high speed as long as a laser field of sufficiently high intensity is available.展开更多
The paper discusses the experimental results pointing to the efficient channel of the CO vibrational to the C2 electronic energy-transfer. The radiation spectra of the d3Hg electronic state of C2 molecule are investig...The paper discusses the experimental results pointing to the efficient channel of the CO vibrational to the C2 electronic energy-transfer. The radiation spectra of the d3Hg electronic state of C2 molecule are investigated and the relation of their kinetics to a vibrational excitation of CO molecules in the He-CO-O2 plasma is discussed. The changes of CO VED (vibrational energy distribution) were imposed by an application of a laser resonator to the discharge tube under investigation. Strong correlation has been found in experiments between concentrations of vibrationally excited CO molecules and the electronically excited state d31qg of C2 molecule. Modulation of the intensity of lasing oscillation cased marked modulation of the intensity of the emission from d3Hg (Swan bands). It was found that the vibrational levels 12 〈 w 〈 20 of the CO molecules most effect on the concentration of the C2 (d3flg). The facts discussed above most probably point to the existence of efficient channel for the VE energy transfer: CO (w) + C2 →CO + C2 (d3II). The efficiency of this channel increases with the growth of populations of high vibrational levels of CO (X1∑, w).展开更多
The photodissociation dynamics of IC1 has been studied near 304 and 280 nm on a simple miniature time of flight (mini-TOF) photofragment translational spectrometer with a short pulse of a weak acceleration field. An i...The photodissociation dynamics of IC1 has been studied near 304 and 280 nm on a simple miniature time of flight (mini-TOF) photofragment translational spectrometer with a short pulse of a weak acceleration field. An intense hot band effect was ob- served. Many small peaks were resolved in each photofragment translational spectrum (PTS). Based on simulations, the principal peaks were assigned not only to the different photodissociation channels (1) I + C1, (2) I + CI*, (3) I* + C1, or (4) I* + CI*, but also to the different chlorine isotopes (35C1 and 37C1). Moreover, some extra peaks showed the existence of an intense hot band effect from vibrationally excited ICI molecules, though only a few percent of ICI molecules remained in the vibrationally excited states in our supersonic molecular beam. Based on the spectra near 304nm, the quantum yield Φ of each channel, the curve crossing, and the branching fraction a from each transition state were determined.展开更多
文摘The Raman and infrared spectra of all-trans-astaxanthin (AXT) in dimethyl sulfoxide (DMSO) solvent were investigated experimentally and theoretically. Density functional cal-culations of the Raman spectra predict the splitting of the υ1 band into υ1-1 and υ1-2 compo-nents. The absence of splitting in Raman experimental spectra is ascribed to the competition between the two symmetric C=C stretching vibrations of the backbone chain. The υ1 band is very sensitive to the excitation wavelength: resonance excitation stimulates the higher-frequency υ1-2 mode, and off-resonance excitation corresponds to the lower-frequency υ1-1 mode. Analyses of the intramolecular hydrogen bonding between C=O and O-H in the AXT/DMSO system reveal that the C4=O1...H1-O3 and C4'=O2...H2-O4 bonds are strengthened and weakened, respectively, in the electronically excited state compared with those in the ground state. This result reveals significant variations of the AXT molecular structure in different electronic states.
文摘We report the preparation of D2 molecules in v=2 level in molecular beam condition. A single longitudinal mode laser system was used for excitation of D2 from (v=0, j=0) to (v=2, j=0) with the scheme of stimulated Raman pumping. An excitation efficiency of 25.2% has been achieved, which was determined by the scheme of resonance-enhanced multiphoton ion- ization. Dependence of relative excitation efficiency on laser energy has been measured. We found that the increasing rate of excitation efficiency became slower as pulse energy of Stokes laser increase, while the excitation efficiency still increases approximately linearly with pump pulse energies up to 60 mJ. The spectral line shapes of Raman transition was also measured at different laser energies and considerable dynamical Stark effect was observed. A single peak was found on the three dimension surface of relative excitation efficiency, indicating the process occurred in the present study is a process of stimulated Raman pumping instead of stimulated adiabatic Raman passage.
文摘We study the H+CH4/CD4-+H2/HD+CH3/CD3 reactions using the time sliced velocity map ion imaging technique. Ion images of the CH3/CD3 products were measured by the (2+1) resonance enhanced multi-photon ionization (REMPI) detection method. Besides the CH3/CD3 products in the ground state, ion images of the vibrationally excited CH3/CD3 products were also observed at two collision energies of 0.72 and 1.06 eV. It is shown that the angular distribution of the products CH3/CD3 in vibrationally excited states gradually vary from backward scattering to sideways scattering as the collision energy increases. Compared to the CH3/CD3 products in the ground state, the CH3/CD3 products in vibrationally excited states tend to be more sideways scattered, indicating that larger impact parameters play a more important role in the vibrationally excited product channels.
文摘Preparation of a high flux of hydrogen molecules in a specific vibrationally excited state is the major prerequisite and challenge in scattering experiments that use vibrationally excited hydrogen molecules as the target. The widely used scheme of stimulated Raman pumping suffers from coherent population return which severely limits the excitation efficiency. Re- cently we successfully transferred D2 molecules in the molecular beam from (v=0, J=0) to (v=1, J=0) level, with the scheme of Stark-induced adiabatic Raman passage. As high as 75% of the excitation efficiency was achieved. This excitation technique promise to be a unique tool for crossed beam and beam-surface scattering experiments which aim to reveal the role of vibrational excitation of hydrogen molecules in the chemical reaction.
基金National Natural Science Foundation ofChina (No.10274051) and Shanghai Nat-ural Science Foundation(No.03ZR14060)
文摘It is theoretically shown that excitonic Doppler-Rabi oscillations can occur in an organic slab moving along the axis of a high-Q cavity. Due to the N enhancement of the vacuum Rabi frequency, this effect can be more eas ily observed than that in a moving two-level atom.
基金supported by the Ministry of Science and Technology (No.2017YFF0104500)the Chinese Academy of Sciences (No.XDB17000000)the National Natural Science Foundation of China (No.21573226, No.21822305)
文摘The reaction dynamics of the fluorine atom with vibrationally excited D2(v=1, v=0) was investigated using the crossed beam method. The scheme of stimulated Raman pumping was employed for preparation of vibrationally excited D2 molecules. Contribution from the reaction of spin-orbit excited F*(2P1/2) with vibrationally excited D2 was not found. Reaction of spin-orbit ground F(2P3/2) with vibrationally excited D2 was measured and DF products populated in v'=2, 3, 4, 5 were observed. Compared with the vibrationally ground reaction, DF products from the vibrationally excited reaction of F(2P3/2)+D2(v=1, j=0) are rotationally “hotter”. Differential cross sections at four collision energies, ranging from 0.32 kcal/mol to 2.62 kcal/mol, were obtained. Backward scattering dominates for DF products in all vibrational levels at the lowest collision energy of 0.32 kcal/mol. As the collision energy increases, angular distribution of DF products gradually shifts from backward to sideway. The collision-energy dependence of differential cross section of DF(v’=5) at forward direction was also measured. Forward-scattered signal of DF(v'=5) appears at the collision energy of 1.0 kcal/mol, and becomes dominated at 2.62 kcal/mol.
基金The project supported by National Fundamental Research Program of China under Grant No. 2005CB724508 and National Natural Science Foundation of China under Grant Nos. 60478029, 90503010, and 10575040 .We would like to thank enlightening discussions professor Wu Ying for many
文摘In this paper, a procedure is proposed for measuring Wigner characteristic function for motion of a single trapped ion. In the scheme, the trapped ion is driven by two laser beams with different frequencies tuned to the first lower and upper vibrational sidebands, respectively. Unlike other previous scheme, our scheme does not require the displacement of the external state before the ion-laser interaction and thus our scheme night be more simple and feasible. The scheme can also be used to prepare the motional Schroedinger cat states and entangled coherent states.
基金Supported by Key Program of National Natural Science Foundation of China under Grant No. 60931002National Natural Science Foundation of China under Grant No.10704001+3 种基金Anhui Provincial Natural Science Foundation under Grant No. 070412060the Major Program of the Education Department of Anhui Province under Grant No. KJ2010ZD08the Key Program of the Education Department of Anhui Province under Grant No. KJ2010A287the Personal Development Foundation of Anhui Province under Grant No. 2009Z022
文摘In this paper, we propose a scheme for generating an arbitrary three-dimensional pure state of vibrational motion of a trapped ion. Our scheme is based on a sequence of laser pulses, which are tuned to the appropriate vibrational sidebands with respect to the appropriate electronic transition.
文摘We propose a scheme for the generation of entangled coherent states for the center-of-mass and relative vibrational modes of two trapped ions. In the scheme the ions are simultaneously illuminated by a single standing-wave laser tuned to the carrier. The scheme allows the production of an entangled coherent states with a considerably high speed as long as a laser field of sufficiently high intensity is available.
文摘The paper discusses the experimental results pointing to the efficient channel of the CO vibrational to the C2 electronic energy-transfer. The radiation spectra of the d3Hg electronic state of C2 molecule are investigated and the relation of their kinetics to a vibrational excitation of CO molecules in the He-CO-O2 plasma is discussed. The changes of CO VED (vibrational energy distribution) were imposed by an application of a laser resonator to the discharge tube under investigation. Strong correlation has been found in experiments between concentrations of vibrationally excited CO molecules and the electronically excited state d31qg of C2 molecule. Modulation of the intensity of lasing oscillation cased marked modulation of the intensity of the emission from d3Hg (Swan bands). It was found that the vibrational levels 12 〈 w 〈 20 of the CO molecules most effect on the concentration of the C2 (d3flg). The facts discussed above most probably point to the existence of efficient channel for the VE energy transfer: CO (w) + C2 →CO + C2 (d3II). The efficiency of this channel increases with the growth of populations of high vibrational levels of CO (X1∑, w).
基金supported by the National Natural Science Foundation of China (20433080)
文摘The photodissociation dynamics of IC1 has been studied near 304 and 280 nm on a simple miniature time of flight (mini-TOF) photofragment translational spectrometer with a short pulse of a weak acceleration field. An intense hot band effect was ob- served. Many small peaks were resolved in each photofragment translational spectrum (PTS). Based on simulations, the principal peaks were assigned not only to the different photodissociation channels (1) I + C1, (2) I + CI*, (3) I* + C1, or (4) I* + CI*, but also to the different chlorine isotopes (35C1 and 37C1). Moreover, some extra peaks showed the existence of an intense hot band effect from vibrationally excited ICI molecules, though only a few percent of ICI molecules remained in the vibrationally excited states in our supersonic molecular beam. Based on the spectra near 304nm, the quantum yield Φ of each channel, the curve crossing, and the branching fraction a from each transition state were determined.