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1.
An interaction potential for an N2(X1σg+) molecule is constructed by using the highly accurate
valence internally contracted multireference configuration
interaction method and the largest basis set, aug-cc-pV6Z, in the
valence range. The potential is used to investigate the elastic
scattering of two N atoms at energies from 1.0× 10-11
to 1.0× 10-4 a.u. The derived total elastic cross
sections are very large and almost constant at ultralow
temperatures, and the shape of total elastic cross section curve is
mainly dominated by the s-partial wave at very low collision
energies. Three shape resonances are found in the total elastic
cross sections. Concretely, the first one is very sharp and strong.
It results from the g-partial-wave contribution and the resonant
energy is 3.645× 10-6 a.u. The second one is contributed
by the h-partial wave and the resonant energy is 1.752× 10-5 a.u. This resonance is broadened by those from the d- and
f-partial waves. The third one comes from the l = 6 partial wave
contribution and the resonant energy is 3.522× 10-5 a.u.
This resonance is broadened by those from the g- and h-partial
waves. The N2(X1σg+) molecular
parameters, which are determined at the current theoretical level,
achieve very high accuracy due to the employment of the largest
correlation-consistent basis set in the valence range. 相似文献
2.
The splitting of potential energy curves for the states
$X^{2}\Pi _{3/2}$, $^{2}\Pi _{1/2}$ and $A^{2}\Sigma ^{ +}$ of
hydroxyl OH under spin--orbit coupling (SOC) has been calculated by
using the SO multi-configuration quasi-degenerate perturbation theory
(SO-MCQDPT). Their Murrell--Sorbie (M--S) potential functions have been
derived, then, the spectroscopic constants for $X^{2}\Pi _{3/2}$,$^{
2}\Pi _{1/2}$ and $A^{2}\Sigma ^{ + }$ have been derived from the
M--S function. The calculated dissociation energies for the three states are
$D_{0}$[OH($X^{2}\Pi _{3/2})$]=34966.632cm$^{-1}$,
$D_{0}$[OH($^{2}\Pi _{1/2})$]=34922.802cm$^{-1}$, and
$D_{0}$[OH($A^{2}\Sigma ^{ + })$]=17469.794cm$^{-1}$, respectively. The
vertical excitation energy $\nu [ {{ }^2\Pi _{1/2} ( {\nu = 0}
) \to {X}{ }^2\Pi _{3/2} ( {\nu = 0} )} ] =
139.6{\rm cm}^{-{\rm 1}}$. All the spectroscopic data for the
$X^{2}\Pi _{3/2}$ and $^{2}\Pi _{1/2 }$ are given for the
first time except the dissociation energy of $X^{2}\Pi _{3/2}$. 相似文献
3.
Elastic collisions of sulfur and hydrogen in their ground states at low temperatures and spectroscopic parameters of SH(X^2∏) radical
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This paper constructs the interaction potential of the SH(X^2∏) radical by using the coupled-cluster singlesdoubles-approximate-triples theory combining the correlation-consistent quintuple basis set augmented with the diffuse functions, aug-cc-pV5Z, in the valence range. Employing the potential, it accurately determines the spectroscopic parameters. The present De, Re, ωe, ωeχe, ae and Be values are of 3.7767eV, 0.13424nm, 2699.846 cm^-1, 47.7055 cm^-1, 0.2639cm^-1 and 9.4414 cm^-1, respectively, which are in excellent agreement with those obtained from the measure- ments. A total of 19 vibrational states has been found when J = 0 by solving the radial SchrSdinger equation of nuclear motion. The complete vibrational levels, classical turning points, initial rotation and centrifugal distortion constants when J = 0 are reported for the first time, which are in good accord with the experimental results. The total and various partial-wave cross sections are computed for the elastic collisions of sulfur and hydrogen in their ground states at low temperatures when two atoms approach each other along the SH(X^2∏) potential energy curve. Over the impact energy range from 1.0×10^-11 to 1.0×10^-4 a.u., eight shape resonances have been found in the total elastic cross sections. For each shape resonance, the resonant energy is accurately calculated. Careful investigations have pointed out that these resonances result from the 1 = 0, 1, 2, 3, 4, 6, 7, 8 partial-wave contributions. 相似文献
4.
Oscillator strengths for 22S--n2P transitions of the lithium isoelectronic sequence from Z = 11 to 20
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The dipole-length, dipole-velocity and dipole-acceleration absorption oscillator strengths for the 1s22s-1s2np (3≤n≤9) transitions of lithium-like systems from Z=11 to 20 are calculated by using the energies and the multiconfiguration interaction wave functions obtained from a full core plus correlation method, in which relativistic and mass-polarization effects on the energy, as the first-order perturbation corrections, are included. The results of three forms are in good agreement with each other, and closely agree with the experimental data available in the literature. Based on the quantum defects obtained with quantum defect theory (QDT), the discrete oscillator strengths for the transitions from the ground state to highly excited states 1s2np (n≥10) and oscillator strength densities corresponding to the bound-free transitions are obtained for these ions. 相似文献
5.
This paper studies the process of mutual neutralization of Si^+ and H^- ions in slow collisions within the multichannel Landau-Zener model. All important ionic-covalent couplings in this collision system are included in the collision dynamics. The cross sections for population of specific final states of product Si atom are calculated in the CM energy range 0.05 e∨/u-5 ke∨/u. Both singlet and triplet states are considered. At collision energies below -10 e∨/u, the most populated singlet state is Si(3p4p, ^1S0), while for energies above -150e∨/u it is the Si(3p, 4p, ^1P1) state. In the case of triplet states, the mixed 3p4p(^3S1 +^3P0) states are the most populated in the entire collision energy range investigated. The total cross section exhibits a broad maximum around 200 300e∨/u and for ECM ≤ 10e∨/u it monotonically increases with decreasing the collision energy, reaching a value of 8 × 10^-13 cm^2 at ECM = 0.05 e∨/u. The ion-pair formation process in Si(3p^2 ^3PJ)+H(1s) collisions has also been considered and its cross section in the considered energy range is very small (smaller than 10^-20 cm^2 in the energy region below 1 ke∨/u). 相似文献
6.
A new global potential energy surface of the ground state of SiH2+ (X2A1) system and dynamics calculations of the Si+ + H2 (v0 = 2, j0 = 0) → SiH+ + H reaction
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Yong Zhang 《中国物理 B》2022,31(11):113101-113101
A global potential energy surface (PES) of the ground state of SiH$_{2}^{+}$ system is built by using neural network method based on 18223 ab initio points. The topographic properties of PES are presented and compared with previous theoretical and experimental studies. The results indicate that the spectroscopic parameters obtained from the new PES are in good agreement with the experimental data. In order to further verify the validity of the new PES, a test dynamics calculation of the Si$^{+} +$ H$_{2}$ ($v_0 = 2, j_{0} = 0$) $\to $ H $+$ SiH$^{+}$ reaction has been carried out by using the time-dependent wave packet method. The integral cross sections and rate constants are computed for the title reaction. The reasonable dynamical behavior indicates that the newly constructed PES is suitable for relevant dynamics investigations. 相似文献
7.
Hyperfine structure and isotope shifts in five optical
transitions: 424.5 nm (
–
), 537.2 nm (
–
), 554.5 nm
(
–
), 560.9 nm
(
–
) and 666.0 nm
(
–
)
of Pb II have been measured. As a light source the discharge tube was used.
The hyperfine structure measurements were
performed using metallic isotope 207Pb. For isotope shifts
measurements natural lead was used. The high resolution spectral apparatus consisted of a silver
coated Fabry-Perot etalon and a grating spectrograph combined
with a CCD camera used as a detector. In the analysis of the
spectra a computer simulation technique was used. The hyperfine
structure observations yielded the splitting constants A for
seven levels of Pb II. The isotope shift studies enabled to
separate the mass and the field shifts and to determine values of
changes of the mean square nuclear charge radii. 相似文献
8.
The interaction potential of a He-BH complex is investigated by the coupled-cluster single-double plus pertur-bative triples (CCSD (T)) method and an augmented correlation consistent polarized valence (aug-cc-pV)5Z basis set extended with a set of (3s3p2d1f1g) midbond functions. Using the five two-dimensional model potentials, the first three-dimensional interaction potential energy surface is constructed by interpolating along (r–r e ) by using a fourth-order polynomial. The cross sections for the rovibrational relaxation of BH in cold and ultracold collisions with 3 He atom are calculated based on the three-dimensional potential. The results show that the Δv =-1 transition is more efficient than the Δv =-2 transition, and that the process of relaxation takes place mainly between rotational energy levels with the same vibration state and the Δj =-1 transition is the most efficient. The zero temperature quenching rate coefficient is finite as predicted by Wigner’s law. The resonance is found to take place around 0.1–1 cm-1 translational energy, which gives rise to a step in the rate coefficients for temperatures around 0.1–1 K. The final rotational distributions in the state v = 0 resulting from the quenching of state (v = 1, j = 0) at three energies corresponding to the three different regimes are also given. 相似文献
9.
Investigation of analytical harmonic frequency and potential energy function,vibrational levels for the X^2∑^+ and A^2Л states of CN radical
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This paper calculates the equilibrium structure and the potential energy functions of the ground state (X^2∑^+) and the low lying excited electronic state (A^2Л) of CN radical are calculated by using CASSCF method. The potential energy curves are obtained by a least square fitting to the modified Murrell-Sorbie function. On the basis of physical theory of potential energy function, harmonic frequency (ωe) and other spectroscopic constants (ωeχe, βe and αe) are calculated by employing the Rydberg-Klei-Rees method. The theoretical calculation results are in excellent agreement with the experimental and other complicated theoretical calculation data. In addition, the eigenvalues of vibrational levels have been calculated by solving the radial one-dimensional SchrSdinger equation of nuclear motion using the algebraic method based on the analytical potential energy function. 相似文献
10.
Study on spectroscopic parameters and molecular constants of HCl(X~1Σ~+) molecule by using multireference configuration interaction approach
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Equilibrium internuclear separations, harmonic frequencies
and potential energy curves (PECs) of HCl($X^{1}\Sigma ^{ + })$
molecule are investigated by using the highly accurate valence
internally contracted multireference configuration interaction
(MRCI) approach in combination with a series of
correlation-consistent basis sets in the valence range. The PECs are
all fitted to the Murrell--Sorbie function, and they are used to
accurately derive the spectroscopic parameters ($D_{\rm e}$,
$D_{0}$, $\omega_{\rm e}\chi_{\rm e}$, $\alpha_{\rm e}$ and $B_{\rm
e})$. Compared with the available measurements, the PEC obtained at
the basis set, aug-cc-pV5Z, is selected to investigate the
vibrational manifolds. The constants $D_{0}$, $D_{\rm e}$, $R_{\rm
e}$, $\omega_{\rm e}$, $\omega_{\rm e}\chi_{\rm e}$, $\alpha_{\rm
e}$ and $B_{\rm e}$ at this basis set are 4.4006~eV, 4.5845~eV,
0.12757~nm, 2993.33~cm$^{ - 1}$, 52.6273~cm$^{ - 1}$, 0.2981~cm$^{ -
1}$ and 10.5841~cm$^{ - 1}$, respectively, which almost perfectly
conform to the available experimental results. With the potential
determined at the MRCI/aug-cc-pV5Z level of theory, by numerically
solving the radial Schr\"{o}dinger equation of nuclear motion in the
adiabatic approximation, a total of 21 vibrational levels are
predicted. Complete vibrational levels, classical turning points,
inertial rotation and centrifugal distortion constants are
reproduced, which are in excellent agreement with the available
Rydberg--Klein--Rees data. Most of these theoretical vibrational
manifolds are reported for the first time to the best of our
knowledge. 相似文献
11.
This paper calculates the transition wavelengths and probabilities
of the two-electron and one-photon (TEOP) transition from the
$(3{\rm s}^{-1}_{1/2}4{\rm d}_{j})_{J=1,2}$ to $(3{\rm
p}^{-1}_{3/2}4{\rm s}_{1/2})_{J=1}$ and the $(3{\rm
p}^{-1}_{1/2}4{\rm s}_{1/2})_{J=1}$ to $(3{\rm d}^{-1}_{j}4{\rm
d}_{j'})_{J=1,2}$ for highly charged Ni-like ions with atomic number
$Z$ in the range $47\leq Z\leq92$. In the calculations, the
multi-configuration Dirac--Fock method and corresponding program
packages GRASP92 and REOS99 were used, and the relativistic effects,
correlation effects and relaxation effects were considered
systematically. It is found that the TEOP transitions are very
sensitive to the correlation of electrons, and the probabilities
will be enhanced sharply in some special $Z$ regions along the
isoelectronic sequence. The present TEOP transition wavelengths are
compared with the available data from some previous publications,
good agreement is obtained. 相似文献
12.
Investigation of isotope effects of dynamic properties for H(D) +OF reactions by the quasi-classical trajectory method
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Quasi-classical trajectory (QCT) calculations are employed
to study the dynamic properties for \mbox{H(D)} + \mbox{OF}
reactions on the adiabatic potential energy surface (PES) of the
\mbox{1}{ }^{3}\mbox{A}' triplet state. Obvious differences
between the reaction probabilities for J = 0, integral cross
sections for J \ne 0, branch ratios of the product and
internuclear distances as well as product rotational alignments
between the title reactions are found. These differences are
attributed mainly to the different reduced masses of the reactants
and the different zero-point energies (ZPEs) of the transition
state. 相似文献
13.
Using a neutral N2 beam as target,this paper studies the dissociation of N2+ in intense femtosecond laser fields(45 fs,~1×10 16 W/cm 2) at the laser wavelength of 800 nm based on the time-of-flight mass spectra of N + fragment ions.The angular distributions of N+ and the laser power dependence of N + yielded from different dissociation pathways show that the dissociation mechanisms mainly proceed through the couplings between the metastable states(A,B and C) and the upper excited states of N2+.A coupling model of light-dressed potential energy curves of N+2 is used to interpret the kinetic energy release of N+. 相似文献
14.
Ab initio calculation of the total dielectronic
recombination (DR) rate coefficient from the ground state of Co-like
tantalum is performed using the relativistic distorted-wave
approximation with configuration interaction. The contributions to
the total DR rate coefficients are explicitly calculated from the
complexes of Ni-like tantalum: 3s23p63d3/23 3d5/26
n'l', 3s23p53d10n'l', 3s3p63d10n'l',
3s23p63d84ln'l', 3s23p53d94ln'l' and
3s3p63d94ln'l' with n' ≤ 25, and
3s23p63d85ln'l' with n' ≤ 9. The l' and n'
dependences of partial DR rate coefficients are investigated. The
contributions from higher n'complexes are evaluated by a
level-by-level extrapolation method. The total DR rate coefficients
mainly come from the complex series 3s23p63d84ln'l',
3s23p53d94ln'l' and are fitted to an empirical formula with
high accuracy. Comparison of the present results with those of other
works shows that the previously published data underestimate
significantly the DR rates of Co-like tantalum. 相似文献
15.
Elastic collisions between Si and D atoms at low temperatures and accurate analytic potential energy function and molecular constants of the SiD(χ^2П) radical
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Interaction potential of the SiD(X2Π) radical is constructed by using the CCSD(T) theory in combination with the largest correlation-consistent quintuple basis set augmented with the diffuse functions in the valence range. Using the interaction potential, the spectroscopic parameters are accurately determined. The present D0, De, Re, ωe, αe and Be values are of 3.0956 eV, 3.1863 eV, 0.15223 nm, 1472.894 cm-1, 0.07799 cm-1 and 3.8717 cm-1, respectively, which are in excellent agreement with the measurements. A total of 26 vibrational states is predicted when J=0 by solving the radial Schro¨dinger equation of nuclear motion. The complete vibrational levels, classical turning points, initial rotation and centrifugal distortion constants when J=0 are reported for the first time, which are in good accord with the available experiments. The total and various partial-wave cross sections are calculated for the elastic collisions between Si and D atoms in their ground states at 1.0×10-11–1.0×10-3 a.u. when the two atoms approach each other along the SiD(X2Π) potential energy curve. Four shape resonances are found in the total elastic cross sections, and their resonant energies are of 1.73×10-5, 4.0×10-5, 6.45×10-5 and 5.5×10-4 a.u., respectively. Each shape resonance in the total elastic cross sections is carefully investigated. The results show that the shape of the total elastic cross sections is mainly dominated by the s partial wave at very low temperatures. Because of the weakness of the shape resonances coming from the higher partial waves, most of them are passed into oblivion by the strong s partial-wave elastic cross sections. 相似文献
16.
本文详细介绍计算电子碰撞激发散射截面的扭曲波玻恩近似(DWBA)理论模型,并对低能DWBA模型进行修正。利用修正的DWBA模型计算了电子碰撞激发氢原子和氦离子1s-2s 和1s-2p的散射微分截面。将关于氢原子由基态到n=2态的电子碰撞激发散射微分截面与绝对实验测量数据比较,发现二者符合得很好,这验证了我们对DWBA修正的正确性。本文工作为拟合强场诱导的氦原子非序列双电离关联电子动量谱提供了有效的理论方法。 相似文献
17.
本文采用多组态相互作用及Davidson修正方法和全电子基组计算了SH~-阴离子的X~1∑~+,a~3∏和A~1∏态的势能曲线、电偶极矩和跃迁偶极矩.计算的光谱常数与实验值及已有的理论值符合得很好.在计算中考虑了自旋-轨道耦合效应.计算得到a~3∏_1(v'=0)?X~1∑_(0+)~+(v"=0)和A~1∏_1(v'=0)?X~1Σ_(0+)~+(v"=0)跃迁具有高对角分布的弗兰克-康登因子,分别为0.9990和0.9999;计算得到a~3∏_1和A~1∏_1态的自发辐射寿命分别为1.472和0.188 ms.A~1∏_1?X~1∑_(0+)~+跃迁存在中间态a~3∏_(0+)和a~3∏_1,但中间态对激光冷却SH~-阴离子的影响可以忽略.分别利用a~3∏_1(v'=0)? X~1∑_(0+)~+(v"=0)和A~1∏_1(v'=0)? X~1∑_(0+)~+(v"=0)跃迁构建了准闭合的能级系统,冷却所需的激光波长分别为492.27和478.57 nm.最后预测了激光冷却SH~-阴离子能达到的多普勒温度和反冲温度.这些结果为进一步实验提供了理论参数. 相似文献
18.
The role of hydrogen in hydrogenated microcrystalline silicon film and in deposition process with VHF-PECVD technique
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The role of hydrogen in hydrogenated microcrystalline silicon ($\mu $c-Si:H)
thin films in deposition processes with very high frequency
plasma-enhanced chemical vapour deposition (VHF-PECVD) technique have been
investigated in this paper. With \textit{in situ} optical emission spectroscopy (OES)
diagnosis during the fabrication of $\mu $c-Si:H thin films under different
plasma excitation frequency $\nu _{\rm e }$ (60MHz--90MHz), the
characteristic peak intensities ($I_{{\rm SiH}^*}$, $I_{{\rm H}\alpha^*}$
and $I_{{\rm H}\beta ^*}$) in SiHVHF-PECVD技术 氢化微晶硅 光发射光谱 薄膜学 VHF-PECVD technique, hydrogenated microcrystalline silicon, role of hydrogen, optical emission spectroscopy Project supported by the Natural Science Foundation of Guangdong
Province, China (Grant No 05300378), the State Key Development Program for Basic Research
of China (Grant Nos G2000028202 and G2000028203) and the Program on Natural
Science of Jinan University, Guangzhou, China (Grant No 51204056). 2005-11-25 2005-11-252006-01-05 The role of hydrogen in hydrogenated microcrystalline silicon (μc-Si:H) thin films in deposition processes with very high frequency plasma-enhanced chemical vapour deposition (VHF-PECVD) technique have been investigated in this paper. With in situ optical emission spectroscopy (OES) diagnosis during the fabrication of μc-Si:H thin films under different plasma excitation frequency Ve (60MHz-90MHz), the characteristic peak intensities (IsiH*, IHα* and IHβ* ) in SiH4+H2 plasma and the ratio of (IHα* + IHβ* ) to IsiH* were measured; all the characteristic peak intensities and the ratio (IHα* + IHβ* )/IsiH* are increased with plasma excitation frequency. It is identified that high plasma excitation frequency is favourable to promote the decomposition of SiH4+H2 to produce atomic hydrogen and SiHx radicals. The influences of atomic hydrogen on structural properties and that of SiHx radicals on deposition rate of μc-Si:H thin films have been studied through Raman spectra and thickness measurements, respectively. It can be concluded that both the crystalline volume fraction and deposition rate are enhanced with the increase of plasma excitation frequency, which is in good accord with the OES results. By means of FTIR measurements, hydrogen contents of μc-Si:H thin films deposited at different plasma excitation frequency have been evaluated from the integrated intensity of wagging mode near 640 cm^-1. The hydrogen contents vary from 4% to 5%, which are much lower than those of μc-Si:H films deposited with RF-PECVD technique. This implies that μc-Si:H thin films deposited with VHF-PECVD technique usually have good stability under light-soaking. 相似文献
19.
In this article, we assume that there exist the pseudoscalar $D\bar{D}_{s0}^*(2317)$ and $D^*\bar{D}_{s1}^*(2460)$ molecular states $Z_{1,2}$ and construct the color singlet-singlet molecule-type interpolating currents to study their masses with the QCD sum rules. In calculations, we consider the contributions of the vacuum condensates up to dimension-10 and use the formula $\mu=\sqrt{M_{X/Y/Z}^{2}-(2{\mathbb{M}}_{c})^{2}}$ to determine the energy scales of the QCD spectral densities. The numerical results, $M_{Z_1}=4.61_{-0.08}^{+0.11}\,\text{GeV}$ and $M_{Z_2}=4.60_{-0.06}^{+0.07}\,\text{GeV}$, which lie above the $D\bar{D}_{s0}^*(2317)$ and $D^*\bar{D}_{s1}^*(2460)$ thresholds respectively, indicate that the $D\bar{D}_{s0}^*(2317)$ and $D^*\bar{D}_{s1}^*(2460)$ are difficult to form bound state molecular states, the $Z_{1,2}$ are probably resonance states. 相似文献
20.
Energy transfer probability in organic electrophosphorescence device with dopant 总被引:1,自引:0,他引:1
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Based on the energy transfer process from host to dopant in an organic
electrophosphorescent (EP) device, the expression of energy transfer
probability ($\eta )$ between the host (TPD) and guest (Ir(ppy)$_{3})$ EP
systems was proposed. The results show that: ({1}) The rate of the triplet
energy transfer ($K_{\rm HG}$ and $K_{\rm GH})$ increases exponentially with
increasing donor-acceptor molecular distance ($R$), whereas decreases as the
intermolecular distance ($R_{\rm HH})$ increases from 0.8 to 2.4 nm.
Furthermore, $K_{\rm GH}$ changes more quickly than $K_{\rm HG.}$ ({2}) The energy
transfer probability ($\eta )$ increases as $R$ reduces, and the $R_{\rm HH}$
changes can be safely neglected for $R<$0.9 nm. The situation changes for
0.9nm$ < R < 1.1$nm, $R_{\rm HH }$ ($<1$nm) plays an essential role when
$\eta $ changes
and increases with the latter. However, if $R > 1.1$nm, the transfer
probability will be below zero. Here, the energy transfer principle may be
less important, and the high electroluminescence (EL) quantum efficiency of
phosphorescent system will be attributed to the direct electron-hole
recombination in phosphorescent molecules. ({3}) The $\eta $ will increase when the
Forster radius ($R_{0})$ increases or Gibb's energy decreases. 相似文献