Excited atomic state of Li

An optical transition of 3489 A has been shown to arise from Li using beam foil spectroscopic technique. The mean life of the state emitting this radiation has been measured to be 2.23 ä 0.08 n sec.     

Excited state absorption in CaMoO4

We report the first measurement of excited state absorption (ESA) in a calcium molybdate (CaMoO₄) crystal, and compare the ESA spectrum with a stimulated emission spectrum calculated in terms of the McCumber theory of phonon terminated lasers. It appears that the magnitude of ESA would preclude laser action in this crystal. The temporal ESA dependence has been measured and discussed in terms of the most likely assignment of energy levels involved in ESA.     

Excited state absorption of Ag--centres in RbBr

The induced absorption of Ag^--centres in RbBr pumped by a strong excimer laser pulse is measured over a wide spectral range (250 to 950 nm) using a weak cw probe beam (Xe-lamp). A strong transient absorption around 510 nm is observed and is attributed to the intraionic transition from the relaxed excited 5 ³P₁ state to upper S- or D-levels.     

The ground state of propynal

The millimeter wave spectrum of propynal, HCCCHO, has been studied in the ground vibrational state. A detailed centrifugal distortion analysis has been carried out on the combined data of newly assigned millimeter wave rotational transitions (up to 200 GHz) together with the microwave transitions reported earlier. A total of 90 transitions as high as J = 20 and K = 12 could be fitted with a standard deviation of 87 kHz. This analysis yielded a complete set of ground state rotational and centrifugal distortion constants. The rotational constants are in MHz:

$\text{A = 68 035.2994 ± 0.0429,}$

$\text{B =}\text{4826.3014 ± 0.0073,}$

$\text{C =}\text{4499.5107 ± 0.0069.}$

     

Octupole vibrations and ground state correlations

The relationship between ground-state correlations and collectiveness is investigated for the case of low-lying nonrotational states in the rare earth nuclei. Both octupole and quadrupole modes of excitation are studied and the quasiparticle virtual populations associated with each of them are discussed. The relative importance of particle-particle and particle-hole interaction matrix elements is also analyzed in connection with the shape of the correlation patterns. The fundamental role of the Nilsson + BCS scheme is emphasized and the consistency of the quasiparticle random-phase approximation is established.     

Excited state quantum phase transitions in many-body systems

Phenomena analogous to ground state quantum phase transitions have recently been noted to occur among states throughout the excitation spectra of certain many-body models. These excited state phase transitions are manifested as simultaneous singularities in the eigenvalue spectrum (including the gap or level density), order parameters, and wave function properties. In this article, the characteristics of excited state quantum phase transitions are investigated. The finite-size scaling behavior is determined at the mean-field level. It is found that excited state quantum phase transitions are universal to two-level bosonic and fermionic models with pairing interactions.     

Excited state positronium formation in low density gases

Excited state Ps atoms formed in low density Ne, Ar and H₂ gases have been observed for the first time. The maximum yield was estimated to be ≈ 5.7 × 10^?2 excited Ps atoms per stopped positron of energy ≈ 16 eV in H₂. This is about 14 times greater than previous maximum yields.     

Excited-state Enhanced Third-order Nonlinearity of Azobenzene Material

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Excited state intramolecular proton transfer mechanism of o-hydroxynaphthyl phenanthroimidazole

By utilizing the density functional theory(DFT) and the time-dependent density functional theory(TDDFT), the excited state intramolecular proton transfer(ESIPT) mechanism of o-hydroxynaphthyl phenanthroimidazole(HNPI) is studied in detail. Upon photo is excited, the intramolecular hydrogen bond is obviously enhanced in the S_1 state, which thus promotes the ESIPT process. Hydrogen bond is shown to be strengthened via comparing the molecular structures and the infrared vibration spectra of the S_0 and S_1 states. Through analyzing the frontier molecular orbitals, we can conclude that the excitation is a type of the intramolecular charge transfer excitation, which also indicates the trend of proton transfer in S_1 state. The vertical excitation based on TDDFT calculation can effectively repeat the absorption and fluorescence spectra of the experiment. However, the fluorescence spectrum of normal structure, which is similar to the spectrum of isomer structure is not detected in the experiment. It can be concluded that the fluorescence measured in the experiment is attributed to both structures. In addition, by analyzing the potential energy curves(PECs) calculated by the B3 LYP functional method, it can be derived that since the molecule to cross the potential barrier in the S_1 state is smaller than in the S_0 state and the reverse proton transfer process in the S_1 state is more difficult than in the S_0 state, the ESIPT occurs in the S_1 state.     

Excited state complex and electroluminescence in TPD-based single layer device

N-N′-diphenyl-N,N′-(bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine) (TPD), was used to fabricate single layer devices (ITO/TPD/Ca/Al). A near-white emission (CIE coordinate of 0.25, 0.24) is observed in electroluminescence (EL) of the single layer device with prominent emission bands at 400, 475 and 670 nm. Steady state and time-resolved emission spectra of spin-coated and annealed TPD films and TRES and TRANES analysis confirmed that emission at 400 and 475 nm are due to monomer and excimer emission, respectively. The origin of the red emission at 670 nm in EL is discussed.     

The acetylene ground state saga

The evolution of high-resolution spectroscopic investigation of the vibration–rotation energy states of acetylene in its ground electronic state is presented, focusing on advances co-authored by the ULB group. The emergence of a global picture accounting for all available spectroscopic fingerprints, at their full accuracy, is highlighted. The contributions of this research to various topics is illustrated, including instrumental developments, local mode trends, quantum vs. classical correspondence, energy vs. time approaches and nucleation processes.     

Supersymmetric ground state wave functions

The construction of explicit supersymmetric ground states is considered in a variety of quantum mechanical systems. For broad classes of supersymmetric hamiltonians it is not difficult to find closed-form zero-energy ground-state wave functions.     

Identification of the Li ground state

The proton-stripping reaction from a ¹¹Be radioactive beam incident on a beryllium target demonstrates that only (7±3)% of the ⁹Li residues in the reaction are in coincidence with the 2.7 MeV γ-ray corresponding to the ⁹Li first excited state. This implies that the previously observed low-energy neutrons from the decay of the unbound nucleus ¹⁰Li represent a direct l=0 transition to the ⁹Li ground state. Consequently, neutron-unbound ¹⁰Li is proven to have the same parity inversion as occurs in the case of ¹¹Be with a  intruder state below the natural parity state.     

氦原子基态能量的Roothaan-Hartree-Fock计算

采用包含两个斯莱特基的双ζ函数说明了利用自洽场法求解基态氦原子Roothaan-Hartree-Fock方程的数值过程,计算得基态能量为-2.862 568 Hartree.利用基态的对称性,提出了通过求解泊松方程来计算库仑算符的方法,给出了交叠矩阵和单电子算符的矩阵元,并对自洽的标准作了讨论.