Population Distribution of Excited States in Cs Electrodeless Discharge Lamp

We measure the intensity of fluorescence spectral lines of Cs atoms in an electrodeless discharge lamp from visible light to the near-infrared region of 400-100Ohm. To build an excited state Faraday anomalous dispersion optical filter, the population ratios between the excited states are calculated by rate equations and the spontaneous transition probabilities. The electrodeless discharge lamp with populations in the excited states can be used to realize the frequency stabilization reference for lasers at multiwavelength and the excited state Faraday anomalous dispersion optical filter for submarine communication applications in blue-green wavelengths to simplify the system.

Adiabatic Potential Energy Surfaces and Photodissociation Mechanisms for Highly Excited States of H_(2)O

Full-dimensional adiabatic potential energy surfaces of the electronic ground state X and nine excited states A,I,B,C,D,D',D'',E' and F of H_(2)O molecule are developed at the level of internally contracted multireference configuration interaction with the Davidson correction.The potential energy surfaces are fitted by using Gaussian process regression combining permutation invariant polynomials.With a large selected active space and extra diffuse basis set to describe these Rydberg states,the calculated vertical excited energies and equilibrium geometries are in good agreement with the previous theoretical and experimental values.Compared with the well-investigated photodissociation of the first three low-lying states,both theoretical and experimental studies on higher states are still limited.In this work,we focus on all the three channels of the highly excited state,which are directly involved in the vacuum ultraviolet photodissociation of water.In particular,some conical intersections of D-E',E'-F,A-I and I-C states are clearly illustrated for the first time based on the newly developed potential energy surfaces(PESs).The nonadiabatic dissociation pathways for these excited states are discussed in detail,which may shed light on the photodissociation mechanisms for these highly excited states.

Atomic population distribution of excited states in He electrodeless discharge lamp

Population ratios between excited states are measured to build the excited state Faraday anomalous dispersion optical filter(ESFADOF). We calculate these values between the excited states according to the spontaneous transition probabilities using rate equations and the measured intensities of fluorescence spectral lines of He atoms in an electrodeless discharge lamp in the visible spectral region from 350 to 730 nm. The electrodeless discharge lamp with populations in excited states can be used to realize the frequency stabilization reference of the laser frequency standard. This lamp can also build ESFADOFs for submarine communication application in the blue-green wavelength to simplify the system without the use of a pump laser.

Imaging Photodissociation Dynamics of MgO at 193 nm

In this work,we used time-sliced ion velocity imaging to study the photodissociation dynamics of Mg O at 193 nm.Three dissociation pathways are found through the speed and angular distributions of magnesium.One pathway is the one-photon excitation of Mg O(X^(1)∑^(+))to Mg O(G^(1)Π)followed by spin-orbit coupling between the G^(1)Π,3^(3)Πand ^(1^(5))Πstates,and finally dissociated to the Mg(^(3)Pu)+O(^(3)Pg)along the 1^(5)Πsurface.The other two pathways are one-photon absorption of Mg O(A^(1)Π)state to Mg O(G^(1)Π)and Mg O(4^(1)Π)state to dissociate into Mg(^(3)P_(u))+O(^(3)P_(g))and Mg(^(1)S_(g))+O(^(1)S_(g)),respectively.The anisotropy parameters of the dissociation pathways are related to the lifetime of the vibrational energy levels and the coupling of rotational and vibronic spin-orbit states.The total kinetic energy analysis gives D0(Mg-O)=21645±50 cm^(-1).

Ultraviolet Photodissociation Dynamics of 1-Pentyl Radical

The ultraviolet （UV） photodissociation of jet-cooled 1-pentyl radical is investigated in the wavelength region of 236-254 nm using the high-n Rydberg-atom time-of-flight （HRTOF） technique. The H-atom photofragment yield spectrum of the 1-pentyl radical shows a broad UV absorption feature peaking near 245 nm, similar to the 2pz→3s absorption bands of ethyl and n-propyl. The center-of-mass translational energy distribution, P（ET）, of the H＋CsH10 product channel is bimodal, with a slow peak at -5 kcal/mol and a fast peak at -50 kcal/mol. The fraction of the average translational energy release in the total available energy, （fT）, is 0.30, with those of the slow and fast components being 0.13 and 0.58, respectively. The slow component has an isotropic product angular distribution, while the fast component is anisotropic with an anisotropy parameter -0.4. The bimodal translational energy and angular distributions of the H＋C5H10 products indicate two H-atom elimination channels in the photodissociation of 1-pentyl： （i） a direct, prompt dissociation from the electronic excited state and/or the repulsive part of the ground electronic state potential energy surface; and （ii） a unimolecular dissociation of internally hot radical in the ground electronic state after internal conversion from the electronic excited state.

Enhanced population of excited single state strategy:Irradiation and ultrasound dual-response and host tumor-driven nanosensitizers construction in triple synergistic therapy

Phototheranostics is an emerging field in synergistic antitumor therapy in which irradiation and sensitizers are combined to produce reactive oxygen species(ROS),bio-images,and high temperatures.All of these are arrived from the energy of sensitizers,which located in excited single state(S_(1)).Undeniably,the decentralization of the S_(1)population indirectly decreases the effect of each individual treatment.In this study,a strategy was proposed for enhancing the S_(1)population,and a sensitizer with mitochondrial targeting property,1,4-indolyl iodinated pyrrolo[3,2-b]pyrrole derivative(2I-TPIS),was assembled into adenosine triphosphate(ATP)-responsive nanoparticles(DPA-2I NPs)to achieve dual responses to irradiation and ultrasonication(US)for application to photo-sonodynamic therapy(PSDT).Compared with monotherapies,2I-TPIS generated more ROS in PSDT,inducing mitochondrial autophagy and apoptosis,which in turn triggered immunogenic cell death(ICD).Subsequently,DPA-2I NPs were constructed and self-assembled with the chemotherapeutic agents DPA-Cd and 2I-TPIS to achieve a triple synergistic strategy involving chemotherapy(CT)and PSDT.DPA-2I NPs exhibited absolute sensitization,intra-tumoral overexpression of ATP,and disassembly.Importantly,the biosafety and potent antitumor efficiency of the DPA-2I NP-based“PSDT+CT”therapy were revealed using a 4T1 tumor model.The study results provide insights into the design of sensitizers possessing a sufficient S_(1)population and a highly efficient tumor ablation capacity derived from molecular structural modulation,further enabling triple synergistic antitumor therapies,and expanding the clinical application of sensitizers.

STUDY ON THE PHENOMENA OF LASER EXCITED POPULATION CHANGE ON RES ONANTLY TRANSITIONAL LOWER LEVEL AND ITS APPLICATION

Ⅰ. INTRODUCTIONLaser-excited atomic fluorescence spectrometry in hollow cathode discharge(HCD) has been widely used in the research field of laser spectroscopy in recent years. Similar to traditional method, information obtained in the researches was direct line nonresonance fluorescence arising from the resonantly transitional upper level. Attention has not been sufficiently paid to the phenomenon of population change on the resonantly transitional lower level due to laser irradiation of plasma in HCD, so

Full-Dimensional Potential Energy Surfaces of Ground(X^(2)A′)and Excited(A^(2)A″)Electronic States of HCO and Absorption Spectrum

In this work,high-fidelity full-dimensional potential energy surfaces(PESs)of the ground(X^(2)A′)and first doublet excited(A^(2)A″)electronic states of HCO were constructed using neural network method.In total,4624 high-level ab initio points have been used which were calculated at Davidson corrected internally contracted MRCI-F12 level of theory with a quite large basis set(ACV5Z)without any scaling scheme.Compared with the results obtained from the scaled PESs of Ndenguéet al.,the absorption spectrum based on our PESs has slightly larger intensity,and the peak positions are shifted to smaller energy for dozens of wavenumbers.It is indicated that the scaling of potential energy may make some unpredictable difference on the dynamical results.However,the resonance energies based on those scaled PESs are slightly closer to the current available experimental values than ours.Nevertheless,the unscaled high-level PESs developed in this work might provide a platform for further experimental and theoretical photodissociation and collisional dynamic studies for HCO system.

Multireference Calculation of the Photodissociation of Benzyl Chloride

The photodissociation mechanism of benzyl chloride （BzCl） under 248 nm has been investigated by the complete active space SCF （CASSCF） method by calculating the geometries of the ground （S0） and lower excited states, the vertical （Tv） and adiabatic （T0） excitation energies of the lower states, and the dissociation reaction pathways on the potential energy surfaces （PES） of SI, TI and T2 states. The calculated results clearly elucidated the photodissociation mechanism of BzCl, and indicated that the photodissociation on the PES of T1 state is the most favorable.

Exploring the effect of aggregation-induced emission on the excited state intramolecular proton transfer for a bis-imine derivative by quantum mechanics and our own n-layered integrated molecular orbital and molecular mechanics calculations

We theoretically investigate the excited state intramolecular proton transfer(ESIPT) behavior of the novel fluorophore bis-imine derivative molecule HNP which was designed based on the intersection of 1-(hydrazonomethyl)-naphthalene-2-ol and 1-pyrenecarboxaldehyde. Especially, the density functional theory(DFT) and time-dependent density functional theory(TDDFT) methods for HNP monomer are introduced. Moreover, the "our own n-layered integrated molecular orbital and molecular mechanics"(ONIOM) method(TDDFT:universal force field(UFF)) is used to reveal the aggregation-induced emission(AIE) effect on the ESIPT process for HNP in crystal. Our results confirm that the ESIPT process happens upon the photoexcitation for the HNP monomer and HNP in crystal, which is distinctly monitored by the optimized geometric structures and the potential energy curves. In addition, the results of potential energy curves reveal that the ESIPT process in HNP will be promoted by the AIE effect. Furthermore, the highest occupied molecular orbital(HOMO) and lowest unoccupied molecular orbital(LUMO) for the HNP monomer and HNP in crystal have been calculated. The calculation demonstrates that the electron density decrease of proton donor caused by excitation promotes the ESIPT process. In addition, we find that the variation of atomic dipole moment corrected Hirshfeld population(ADCH) charge for proton acceptor induced by the AIE effect facilitates the ESIPT process. The results will be expected to deepen the understanding of ESIPT dynamics for luminophore under the AIE effect and provide insight into future design of high-efficient AIE compounds.

H_(2)S第一吸收带振动激发态光解动力学的理论研究

本文利用切比雪夫实波包法研究了不同初始振动态下H_(2)S第一吸收带的光解量子动力学。由于初始振动态的波函数不同,计算得到的吸收光谱以及产物的振动态分布表现出不同的动力学特性,由于角坐标波函数的变化,初始伸缩振动激发态(1,0,0)和(0,0,1)的吸收光谱宽度和峰值与振动基态不同,而(0,1,0)振动态的吸收光谱中有两个几乎同样高的峰值.(0,1,0)态的产物振动态分布对激发能量的依赖不强,并由V=0的产物主导,但在(1,0,0)和(0,0,1)振动态的较低能量处占主导的产物是SH(X,V=1)碎片,产物的转动态分布对总能量的依讨赖性较弱,且分布非常冷并在j=1处达到峰值,但(0,1,0)振动态的转动态分布表现出明显的振荡,其各向异性参数随转动量子数的振荡行为不同于其他三种振动态的各向异性参数.

RE：YAG晶体中掺杂离子（HO，Nd，Tm）的最佳浓度

测量了ＲＥ：ＹＡＧ晶体纤维的荧光强度衰减曲线，计算了掺杂稀土离子Ｎｄ、ＨＯ、Ｔｍ的最佳浓度，分别为２，２，７ａｔ．％，并与文献报导的结果进行了比较．

NaYF_4∶Yb^(3+),Er^(3+)上转换荧光纳米体系的红光来源

对Na YF4∶Yb3+,Er3+纳米材料的发光强度与激发光功率的依赖关系进行了研究,分析了Na YF4∶Yb3+,Er3+裸核纳米体系及其核包壳纳米体系的上转换红光真实来源。结果表明:核包壳的纳米体系完全不同于裸核纳米体系,交叉弛豫对于Na YF4∶Yb3+,Er3+纳米体系的上转换红光发射起主导作用,而多声子弛豫过程几乎可以忽略。这个结果对于提高上转换发光纳米材料的上转换效率、调控各发光带之间的相对强度和实现上转换发光的单色性具有重要的指导意义。

Two-Photon Dissociation Dynamics of Hydroxyl Radical

Two-photon dissociation dynamics of the OH radical is studied using the high-n Rydberg atom time-of-flight(HRTOF) technique. The H(2 S)+O(1 D) and H(2 S)+O(1 S) product channels are observed in the dissociation of the OH radical on the 22Π and B2Σ+repulsive states, respectively, from sequential two-photon excitation via the A2Σ+(v′=2, J′=0.5-2.5)state. Both H+O product channels have anisotropic angular distributions, with β=-0.97 for H(2 S)+O(1 D) and 1.97 for H(2 S)+O(1 S). The anisotropic angular distributions are consistent with a mechanism of OH direct dissociation on the repulsive potential energy curves(PECs) leading to the H+O products. The OH bond dissociation energy D0(O-H) is determined to be 35580±15 cm-1.

飞秒激光脉宽对非绝热耦合分子波包运动的影响研究

利用含时波包法研究了强飞秒泵浦-探测激光场中激光脉宽对非绝热耦合NaI分子波包运动的影响.发现波包的振荡周期随脉宽增长而增大,而振荡幅度随脉宽增长而减小.非绝热效应引起的波包在交叉区域的分裂情况影响各态布居.脉宽增长,NaI分子的激发概率增大,而解离概率减小.研究表明调节激光场脉宽可实现对波包运动的控制从而控制态布居的选择性分布.研究结果可以为实验上实现分子的光控制以及量子调控过程提供一定的参考.

基于脉冲整形的激发双重态间的相干布局操控

为了实现红外飞秒脉冲的整形及调控,采用4f系统相位控制技术,实验搭建了脉冲整形装置,并利用整形脉冲对铷原子体系中激发双重态间的相干布居转移进行操控。结果表明,控制抽运脉冲的附加相位,可实现双重态中上激发态的饱和布居,通过修改附加相位函数可将上、下激发态的布居数反转。整形脉冲同样适用于其它的原子和分子系统的相干布居转移的操控。

Photofragment translational spectroscopy at 304 nm from C-H symmetric stretch excited CH_3I [v_1 = 1]

The 304 nm photodissociation of the C-H symmetric stretch excited CH3I[v1=1,v2=0](v1 denotes the C-H symmetric stretch mode,and v2 denotes the umbrella mode)is studied with our simple photofragment translational spectrometer.An IR laser is used to excite the ground state CH3I[0,0]to the C-H symmetric stretch excited CH3I[1,0].With IR laser OFF and ON,the fractions of photofragments CH3(ν1,ν2)from the 304 nm photodissociation of CH3I[1,0]have been determined through the photofragment translational spectra(PTS)from measuring I and I*and also through the PTS from measuring CH3(0,0)(1,0)(0,1)and(1,1).The experimental results show that the C-H symmetric stretch vibration(v1=1)in parent molecules is about 66%retained in the photofragments in the I channel,but only 24%in the I*channel.The populations of photofragments CH3(0,2)and(0,3)are higher than CH3(0,0)and(0,1),showing strong inverted population both in I and I*channels.

Regulated polarization degree of upconversion luminescence and multiple anti-counterfeit applications

Polarization upconversion luminescence(PUCL)of lanthanide ions(Ln^(3+))has been widely used in single particle tracking,microfluidics detection,three-dimensional displays,and so on.However,no effective strategy has been developed for modulating PUCL.Here we report a strategy to regulate PUCL in Ho^(3+)-doped NaYF4single nanorods based on the number of upconversion photons.By constructing a multiphoton upconversion system for Ho^(3+),we regulate the degree of polarization(DOP)of PUCL from 0.590 for two-photon luminescence to 0.929 for three-photon upconversion luminescence(UCL).Furthermore,our strategy is verified from cross-relaxation between Ho^(3+)and Yb^(3+),excitation wavelength,excitation power density,and local site symmetry.And this regulation strategy of PUCL has also been achieved in Tm^(3+),with the DOP ranging from 0.233 for two-photon luminescence to 0.925 for four-photon UCL Besides,multi-dimensional anti-counterfeiting display has been explored with PUCL.This work provides an effective strategy for regulating PUCL and also provides more opportunities for the development of polarization display optical encoding,anti-counterfeiting,and integrated optical devices.

分子光解产生原子激发态集居光谱方法的实验研究

提出一种用Ａｒ＋激光光解Ｃｓ２分子，从而得到Ｃｓ原子５２Ｄ，６２Ｐ态集居的光谱实验方法，并讨论了各种实验参数对原子集居数的影响。