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1.
利用神经网络方法,基于47783个高精度从头算能量点构建了反应体系H+CH4→H2+CH3的一个全域势能面.通过大量的准经典轨线以及量子散射计算测试了势能面的收敛性质.这个势能面对于拟合过程以及从头算点的数目都已经完全收敛,拟合误差很小且比Shepard插值的势能面计算速度更快,代表了此标志性多原子反应体系最好的势能面.  相似文献   

2.
本文在从头算CCSD(T)/AVXZ(X=T,Q)水平上计算了CH4-Ne体系的三维势能面,同时在基组中加入了键函数,并且将基组外推到完全基组极限水平. 通过最小二乘法拟合摩斯长程势能函数形式,获得了三维分析势能面,其中对664个从头算格点的拟合的标准偏差仅为0.042 cm-1. 随后,采用径向离散变量表象和角度有限基组表象相结合的杂化基函数方法,并基于Lanzcos迭代的方法获得了CH4-Ne体系的振转能级,所预测的红外光谱与实验值非常吻合. 本文首次给出了CH4-Ne体系的微波光谱数据. CH4-Ne体系三维摩斯长程势能面分析的表达式为今后CH4在Ne团簇动力学性质以及其碰撞诱导吸收光谱的研究中奠定了基础.  相似文献   

3.
本文采用最近发展的十维含时波包方法研究了H+CH3D→H2+CH2D反应的模式选择性,计算了反应物CH3D在基态、CH3对称和不对称伸缩振动激发态、CD伸缩振动激发态以及CH3弯曲模式的基频和倍频激发态等6个初始状态下的反应几率. 计算结果表明,在碰撞能0.0∽1.0 eV区间内,激发CH3的任意一种伸缩振动模都能增强反应活性,而CD伸缩振动激发对反应的促进作用不明显. CH3弯曲振动模的基频激发对促进反应活性几乎没有影响,由于CH3对称伸缩振动模的基频与CH3弯曲振动模倍频之间的费米共振作用,CH3弯曲振动模的倍频激发显著增强了反应活性.  相似文献   

4.
利用密度泛函理论中杂化泛函理论方法计算了CH2和CH3自由基吸附在Cun(n=1~6)团簇上时C?H对称伸缩振动模式的软化性质,结果表明,CH2在Cun团簇上的吸附要比CH3的吸附强. 计算得到的C-H键的振动频率与实验上测量的这两个自由基吸附在Cu(111)表面的结果符合得很好,随着团簇尺寸的增加,C-H对称伸缩振动频率的软化(红移)越来越大.  相似文献   

5.
利用G3和CBS-QB3的理论方法研究CF3OH分子裂解成FCFO和HF,并考虑大气中双分子和氨气对CF3OH分子裂解的催化作用. 理论计算表明:由于在G3的理论水平下,计算的能垒为188.52 kJ/mol,所以CF3OH分子在大气条件下不可能发生单分子裂解;当氨气和双分子水被加入时,能垒都被降到25.08 kJ/mol,起了强的催化作用. 除此之外,应用过渡态理论对速率常数进行了计算,计算结果表明:氨气催化CF3OH分子的速率常数是单分子和双分子催化CF3OH分子裂解速率常数的109和105倍. 考虑到大气中这些物质的浓度,计算结果预测了氨气催化CF3OH分子裂解在大气中起到重要的作用.  相似文献   

6.
研究了提拉法生长的Er3+/Yb3+:Gd3Sc2Ga3O12和Er3+:Gd3Sc2Ga3O12晶体在室温下320—1700nm范围的吸收光谱和500—750nm范围内的上转换荧光谱,同时对其上转换荧光的可能发生机制、途径以及上转换过程可能对Er3+相似文献   

7.
采用[CCSD(T)]-F12a/aug-cc-pVTZ方法,同时在基组中引入中心键函数(3s3p2d1f1g)构建了He-H$_2$S复合物的高精度六维势能面. 除分子间振动坐标,同时考虑了H2S分子内的v1对称伸缩振动Q1正则模、v2弯曲振动Q2正则模和v3反对称伸缩振动Q3正则模三种振动模式. 将计算得到的六维势能面在Q1,Q2Q3方向上分别做积分得到H2S单体分别处于振动基态、vv3激发态下的He-H2S的三个振动平均势能面. 计算结果表明,每个平均势能面都有一个T形全局极小值、一个平面局部极小值、两个平面内鞍点和一个平面外鞍点. 全局极小值的几何构型位于R=3.46 ?,θ=109.9°和φ=0.0°,势阱深度为35.301 -1. 在径向部分采用离散变量表象法和角度部分采用有限基组表象法并结合Lanczos循环算法计算了He-H2S的振转能级和束缚态. 计算发现He-(para-H2S)在H2S的v2v3区域的带心位移分别为0.025 cm-1和0.031 cm-1,而He-(ortho-H2S)的带心位移分别为0.041 cm-1和0.060 cm-1,都表现为蓝移.  相似文献   

8.
使用单双激发并对三重激发作微扰处理的耦合簇方法计算了Ar2-Ne聚合物的三维势能面. 使用的基组是aug-cc-pVqz并包括3s3p2d2f1g中点键函数. 用二维模型势对7个Ar2键长值的每一个对应的二维格点(R,θ)上的能量进行了拟合. 再将7个二维模型势通过对(r—re) 的六次多项式内插得到三维势能面,并用于随后的振转能级计算,所得到的跃迁频率、光谱常数等与相应的实验结果进行了比较.  相似文献   

9.
秦杰  李佳  李军 《化学物理学报》2021,34(6):649-658
H+SO2→OH+SO反应在燃烧、大气和星际化学中都扮演着重要角色. 它还是具有深势阱中间体形成的典型反应,是检验速率理论和提供有趣反应动力学现象的理想候选反应. 基于之前构建的全维高精度势能面,本文对该反应进行了准经典动力学研究. 在1400 K≤T≤2200 K的温度范围内,计算值重现了实验速率常数. 当反应物SO2处于振-转基态,在31.0∽40.0 kcal/mol的碰撞能范围内,计算得到的积分反应截面随碰撞能增加;在40∽55 kcal/mol的碰撞能范围内,积分反应截面几乎不受碰撞能影响. 产物角度分布呈现对称的前后向双峰结构. 本文还分析了产物OH和SO的振动态分布.  相似文献   

10.
谭鑫鑫  吕树臣 《光子学报》2014,39(7):1169-1175
采用共沉淀法制备了纳米晶ZrO2-Al2O3∶Er3+发光粉体.所制备的粉体室温下具有Er3+离子特征荧光发射,主发射在绿光,其中位于547 nm、560 nm的绿光最强,并得出稀土离子与基质之间有能量传递.对不同煅烧温度下的样品研究表明:因不同温度下所制得的样品晶相不同.研究了纳米晶ZrO2-Al2O3∶Er3+及ZrO2-Al2O3∶Er3+/Yb3+的上转换发光,并分析了上转换的跃迁机制.发现ZrO2-Al2O3∶Er3+的绿光为双光子过程,而ZrO2-Al2O3∶Er3+、Yb3+的上转换光谱中,红光和绿光也为双光子过程,而极弱的蓝光为三光子过程.讨论了Er3+的浓度猝灭现象.最适宜掺杂浓度的原子分数为2%(Er3+/Zr4+).  相似文献   

11.
The high resolution laser Stark spectra of methanol and13C-substituted methanol have been studied up to Stark fields of about 60 000V/cm with the HCN and DCN lasers. Numerous families of absorption lines have been observed in both parallel and perpendicular polarizations. For methanol, the transitions J k =75 64 A, t=0; J k =114 103 E l , t=0; and J k =173 162 E2, t=0 have been identified while the assignments for13C-substituted methanol are J k =148 157 A, t=0; J k =153 142 A+, t=0; J k =107 96 A, t=0; and J k =279 278 E1, t=0. Zero-field frequencies for the assigned transitions are given with improved accuracy over those calculated from available molecular constants, especially for13CH3OH.  相似文献   

12.
Kinetics and mechanisms for reactions of OH with methanol and ethanol have been investigated at the CCSD(T)/6-311 + G(3df2p)//MP2/6-311 + G(3df2p) level of theory. The total and individual rate constants, and product branching ratios for the reactions have been computed in the temperature range 200-3000 K with variational transition state theory by including the effects of multiple reflections above the wells of their pre-reaction complexes, quantum-mechanical tunneling and hindered internal rotations. The predicted results can be represented by the expressions k1 = 4.65 × 10−20 × T2.68 exp(414/T) and k2 = 9.11 × 10−20 × T2.58 exp(748/T) cm3 molecule−1 s−1 for the CH3OH and C2H5OH reactions, respectively. These results are in reasonable agreements with available experimental data except that of OH + C2H5OH in the high temperature range. The former reaction produces 96-89% of the H2O + CH2OH products, whereas the latter process produces 98-70% of H2O + CH3CHOH and 2-21% of the H2O + CH2CH2OH products in the temperature range computed (200-3000 K).  相似文献   

13.
Using a grating-tuned CO2-TEA laser to pump CH3OH in a metallic-wave-guide resonator, submillimeter laser emissions have been produced by pumping with 36 lines in the 9.4m CO2 band and with 23 lines in the 10.6m band. Several dozen new SMM laser lines were observed. Wavelengths accurate to within 0.1% are given for 12 previously unmeasured lines between 34m and 225m.  相似文献   

14.
We have increased the frequency tunability of our CW waveguide CO2 lasers by means of an acoustooptic amplitude modulator, operating at the fixed frequency of 90 MHz. The up-shifted, or down-shifted, laser optical sideband can be generated independently by adjusting the orientation of the modulator. The efficiency is larger than 50%. The frequency tunability of the CO2 laser around each laser line is thus increased by 180 MHz. To demonstrate the possibilities of this method, a source composed of the above modulator and of a CW, 300 MHz tunable waveguide CO2 laser has been used for the search of new large offset FIR laser lines from optically pumped CH3OH and13CH3OH molecules. As a result 15 and 10 new large offset laser lines were discovered respectively. New assignments of some laser lines are also proposed. We have also measured the Stark effect, the offset, and the polarization of other already known lines. In particular a Stark effect frequency tuning of about 1 GHz is demonstrated for a laser line at 208.399 m.  相似文献   

15.
We measured the frequencies of 12 far-infrared laser lines generated in a high- frequency Fabry-Perot laser cavity containing methanol, pumped by a CO2 laser. The frequencies are in the range 2.8 to 11.4 THz (105.4 to 26.2 µm). Ten of the measured frequencies are higher than 7 THz, and help to fill the laser frequency gaps in this region. Five of the measured lines are new. The 11.4 THz line has the highest frequency of an optically pumped laser ever measured with the CO2 laser heterodyne technique.This work has been financed by the Brazilian Government - Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), and by the United States Government - NASA Grant W-18, 623.Contribution of NIST, not subject to U.S. Copyright.  相似文献   

16.
By solving the density matrix equations of a quantum system, the output power intensity of an optically pumped CH3OH FIR laser (CH3OH-OPFIRL) was calculated by means of iteration method, and the spectral characteristics were got. Base on the calculation, optimization of operating parameters including operating gas pressure, pumped power and output coupling coefficient of the CH3OH cavity laser were systematically studied. Experimental, a series of FIR emissions of the CH3OH cavity laser pumped by TEA-CO2 laser with 9P(16) line were measured. The experimental results were in good agreement with theoretical calculations. The project was supported by the Special Research Foundation of Doctorate Station in University of P.R.C.  相似文献   

17.
Using the CH3OH molecular energy levels data base management program, we deduced that when a CH3OH laser pumped by CO2-9P(16) line, there should be a FIR laser line of 918m wavelength, which corresponding to a transition in ground-state reversed three-level energy system. For the first time, the spectra of ground-state reversed three-level system transitions were calculated by solving the density matrix equations, and the spectrum characteristics of 918m line were studied. Experimentally, the CH3OH FIR laser line of 918m wavelength was obtained by pumping with a TEA-CO2 laser. The experimental results were in good agreement with the theoretical calculations.  相似文献   

18.
A total 75 observed vibrational frequencies from 8 isotopomers in methanol have been fitted to a least-squares programme and a set of force constants which includes 21 parameters are obtained. Using this set of parameters, the G and F matrix calculations yield the vibrational frequencies for 10 isotopomers of methanol. The calculated results also show that the different vibrational modes are mixed. This calculation can be readily extended to other similar molecules.  相似文献   

19.
An extensive theoretical and experimental analysis of the absorption and emission spectrum of a CH3OH FIR-laser excited by a conventional CO2 laser is presented. Particular interest is devoted to the Stark shifts of the pump and lasing lines and to the electric field dependence of the Fir-laser output of the various lines. The offsets with respect to the exciting radiation and the Stark shifts of the IR absorption (pump) lines are measured by means of the transferred Lamb dip technique. The theoretical behaviours of the Stark patterns are calculated for several choices of the quantum numbers and selection rules involved in the transitions. A large variety of experimental results are reported and compared to theory. Non-linear Stark shifts have been observed for the 37.5m FIR laser line and for the IR-pump transitions excited by the 9-P(38) and 10-R(38) CO2 laser Lines. Line assignments are proposed and new FIR laser lines are reported.  相似文献   

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