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1.
Some spectroscopic properties of the low-energy electronic states of 9-fluorenone have been examined. The spectra in paraffin matrices at 4.2°K show detailed vibrational spectra. Two fluorescence spectra are observed; a diffuse emission arises from 9-fluorenone crystals in the paraffin matrix, and a sharp emission is characteristic of the molecule. The sharp fluorescence is analyzed in terms of known a1 vibrational fundamentals. The sharp absorption is a near mirror-image to the fluorescence, so Herzberg-Teller vibrations are not prominent. The polarization in the crystal spectrum allows this low-energy transition near 23 000 cm?1 to be assigned . Because there is no vibronic perturbation in fluorescence, and certainly no out-of-plane modes, a transition seen at about 26 000 cm?1 is tentatively assigned . Another sharp absorption system is seen at 31 000 cm?1 in the paraffin matrices at 4.2°K (linewidth 6 cm?1) but no fluorescence was detected. The polarized crystal spectrum indicated the assignment of this system and another very strong system at 40 000 cm?1 to be , while other systems at about 34 000 cm?1 and 44 000 cm?1 are .The phosphorescence spectrum of pyrene-d10 held in a single crystal of 9-fluorenone at 4.2°K has been recorded. No delayed fluorescence from the host crystal is observed at 4.2°K but is intense at 77°K. The energy difference between host and guest triplet levels is estimated to be about 900 cm?1 allowing the lowest triplet state of 9-fluorenone to be placed at 17 800 cm?1. 相似文献
2.
R.M. Lieder A. Neskakis M. Müller-Veggian Y. Gono C. Mayer-Böricke S. Beshai K. Fransson C.G. Linden Th. Lindblad 《Nuclear Physics A》1978,299(2):255-284
High-spin states in 195, 197Tl have been populated with (α, xn) reactions and studied by means of in-beam γ-ray and e? spectroscopic methods. Complementary studies of the decay of 195, 197Pb to 195, 197Tl have been carried out. Several new features have been observed in these nuclei. The bands of 195, 197T1. extended to and , respectively, show a quenching of energy spacings between the , , and states. This has been interpreted as resulting from the coupling of a proton to the ( configurations in the core nuclei 194, 196Hg. Furthermore, positive-parity bands based on states were established up to the and states in 195, 197Tl respectively. Probably these bands originate from the coupling of a h proton to a broken neutron pair. This pair consists of a rotation-aligned neutron and a low-j neutron in the , or shell. It is known to constitute the 5? bands in 194, 196Hg. 相似文献
3.
The non-selective nature of the (α, nγ) reaction has been used to complement information from charged-particle reactions on the level structure of 88Y and 90Y. The γ-ray spectra were recorded with a 25 cm3 Ge(Li) detector at 90° to the beam using primarily targets of 85Rb2CO3 and 87Rb2CO3 and α-particle energies of 11.8, 12.2 and 13.0 MeV. The resulting transitions were accommodated in level schemes that involved primarily the following shell model configurations: , , , in 88Y and , , in 90Y. 相似文献
4.
Levels of the N = 81 nucleus 145Gd have been investigated by in-beam γ-ray and conversion electron spectroscopy with the 144Sm(3He, 2n) reaction. Fourteen new low- and medium-spin states between 1.0 and 2.4 MeV excitation, the known yrast levels up to spin , five other high-spin non-yrast states and a new 20.4 ns isomer at 2200.2 keV in 145Gd have been observed. The isomer decays via a fast 927.3 keV E3 transition with B(E3) = 48 ± 7 W.u. Another weaker decay branch is a mixed, strongly hindered E1 + M2 + E3 transition to the state. We propose an octupole main configuration for the isomer, analogous to the 997 keV isomer in 147Gd. The levels of 145Gd are discussed on the basis of the spherical shell model. 相似文献
5.
Differential cross sections for 87Sr(d, t)86Sr transitions to the states of 86Sr were obtained with the Pittsburgh 18 MeV deuteron beam and the Enge split-pole spectrograph. States of 86Sr up to 3.82 MeV in excitation were studied with a total resolution of 12 keV. Successful distorted-wave Born approximation (DWBA) predictions for 87Sr(d, t) 86Sr angular distributions permitted the extraction of l-values and spectroscopic strengths. The sum-rule value agrees with the observed value for the configuration. The observed strength is spread over 13 states. Contrary to an earlier interpretation, the 0+ ground state is found to contain only 65% of the strength. Similarly, the full 4+ strength is not located in a single state. The new data change the interpretation of the spectrum of 86Sr. They significantly alter the deduced low-spin matrix elements and bring them into much closer agreement with those derived from 88Y. Several new negative-parity states dominated by l = 1 orbital angular momentum transfer have also been identified. 相似文献
6.
The vibration-rotation transitions for v = 1 ← 0 of NO () have been studied by using the technique of laser magnetic resonance spectroscopy. Five magnetic resonance lines are observed with three CO laser lines in the range from 1859 to 1886 cm?1. From these, three zero-field transition frequencies, v = 1 ← 0; , , and are obtained with an accuracy of ±0.0007 cm?1. The molecular constants which have been determined by borrowing centrifugal constants from a previous infrared work are , , and . 相似文献
7.
The spectrum seen in single neutron pickup leading to the doubly odd nucleus 84Rb is remarkably clean, with only five levels populated by l = 4 and six by l = 1 transitions. A simple 2J+1 weighting for the l = 4 data, combined with previous information on 84Rb, allowed the Jπ = 2?–7? states of the () multiplet to be identified. These data are used to determine the two-hole interaction matrix elements. 相似文献
8.
A. Filevich A. Ceballos M.A.J. Mariscotti P. Thieberger E. Der Mateosian 《Nuclear Physics A》1978,295(3):513-524
The 6? and 7? isomeric states in 66Ga and 68Ga at 1440.9 and 1229.6 keV, respectively, have been populated with the (13C, 2np) and (15N, n2p) reactions on natural Fe. The half-lives of these states have been measured to be and . Using previous data on the hyperfine field of Ga in Fe, the g-factors of these states have been determined by means of the TDPAD method. The results are and . These values are in very good agreement with the independent particle model if one assumes the and configurations and uses the empirical proton and neutron g-factors from odd-A neighboring nuclei instead of the Schmidt values. The large disagreements with experiment when Schmidt values are used show that core polarization effects are important in these nuclei. 相似文献
9.
The two emission lines, Kα1α3h and Kα2α3h resulting from the two-electron transitions and were resolved for elemental nickel. Their measured energies agree well with calculations. Their relative intensity and their intensity relative to that of the Kα diagram lines is about 10?4. This is some 104 times larger than both theoretical results and the results of ion-atom collision experiments. 相似文献
10.
B. Fant T. Weckström T. Lönnroth C.J. Herrlander K. Honkanen A. Källberg 《Nuclear Physics A》1984,429(2):296-312
Levels in 208At were populated in the 209Bi(α, 5n) reaction, and the subsequent radiation was studied using γ-spectroscopic methods including γ-ray excitation function and angular distribution, γγ(t) coincidence and γt measurements, as well as measurements of conversion electrons. The excited spectrum of 208At is found to consist of two almost disconnected parts which are proposed to originate from seniority-three proton and neutron cascades. Two isometric states are observed. A state at 1090 keV is proposed to have the main configuration and Jπ = 10?. A high-spin isomer with is assigned to be the state. Shell-model arguments are used to assign configurations to most of the observed levels. Transition rates are discussed. 相似文献
11.
The rise time of the near-infrared fluorescence intensity has been measured in YAG:Nd3+ at room temperature under the excitation by 10 ns duration pulses at 514.5 nm using a time-correlated single photon counting method. The result reveals that the relaxation rate from the pumped level ( + + to the upper level laser level is larger than 108s?1, which is in contrast with the previously reported values of (1.6 ~ 2) × 106s?1. An experiment to search for the visible emission in YAG:Nd3+ gives support to the present value. 相似文献
12.
L Nemes 《Journal of Molecular Spectroscopy》1978,72(1):102-123
Medium resolution infrared grating spectra of gaseous ketene, H2CCO were recorded between 1000 and 400 cm?1, both at instrument temperature (40°C) and with cooling (?40°C). Interferometric Fourier spectra were also measured at ?70°C with resolution 0.22 cm?1 between 450 and 330 cm?1. The K structure of the fundamentals ν5, ν6, ν8, and ν9 was assigned. These fundamentals are coupled by a-axis Coriolis interactions. These couplings were analysed on the symmetric top basis for setting up the perturbation matrix and by utilizing the K-dependent Coriolis shifts of levels. A preliminary analysis of the Coriolis intensity anomalies was also undertaken.Band center values from combination differences are and . Synthetic spectra indicate the band origins of ν8 and ν9 to be close to 977.8 and 439.0 cm?1, respectively. Estimates of Coriolis coupling constants obtained from synthetic spectra are , , , and . Approximate ratios of unperturbed vibrational transition moments obtained from spectral simulations are . 相似文献
13.
M.A.J. Mariscotti H. Beuscher W.F. Davidson Y. Gono H.M. Jäger R.M. Lieder M. Müller-Veggian A. Neskakis D.R. Haenni D.R. Zolnowski 《Nuclear Physics A》1978,311(3):395-412
A level scheme of 144Gd has been established using the 144Sm(α, 4nγ) reaction and in-beam spectroscopy methods. Excitation functions, γ-ray angular distributions, γ-γ coincidence spectra, γ-spectra time related to the cyclotron beam bursts and conversion coefficients for the delayed transitions have been measured.The level scheme comprises 11 levels with spins up to I = 12. Two isomers, a 13 ± 2 ns, 7? state at 2471.4 keV and a 145 ± 30 ns, 10+ state at 3433.0 keV have been observed. The former has similar excitation energy as the 7? isomers in 142Sm, 140Nd and 138Ce and it may arise from the configuration although its lifetime seems to indicate some degree of collectivity. The 10+ state has a similar excitation energy as the 10+ isomer found in 138Ce and it may arise from the dominant configuration. Below the 10+ isomer in 144Gd only two excited states have positive parity; the hitherto known first 2+ and 4+ states. The 11+ and 12+ states must include four-particle configurations or they have to be of collective nature. The latter possibility is supported by the considerable E2/M1 mixture (≈ 20 %) observed for the 11+ to 10+ transition. An analysis of the systematics of ground band levels in the N = 80 isotones shows the same gradual behavior between the two VMI solutions previously found for the Te isotopes. 相似文献
14.
A. Valentin A. Henry Ph. Cardinet M.F. Le Moal Da-Wun Chen K. Narahari Rao 《Journal of Molecular Spectroscopy》1978,70(1):9-17
The wavenumbers of the vibration rotation band lines of 14N16O are reported for the , and subbands of the 1-0 transition in the infrared. The full set of spectroscopic constants for this band has been determined by direct approach using the analysis of Zare, Schmeltekopf, Harrop, and Albritton. In addition to the band origin ν0 and the B, D, H constants for the lower and upper vibrational levels, the following spin-orbit coupling constants have been derived: and (in cm?1). Apparent centrifugal corrections to these constants have been determined and the values obtained for them are and . Λ-Type doubling constants evaluated by using both grating and tunable laser data are also reported. 相似文献
15.
W. Dünnweber E.R. Cosman E. Grosse W.R. Hering P. von Brentano 《Nuclear Physics A》1975,247(2):251-273
A γ-decay scheme for levels in 209Pb up to 4.13 MeV of excitation has been established by means of the reaction 208Pb(d, pγ)209Pb. In high efficiency p-γ coincidence measurements γ-cascades have been observed from the single-particle states and from core-excited states with very small single-particle strength. Assuming a qualitative validity of the weak-coupling model spins and main configurations of particle-core states can be deduced from their γ-decay. The members of the multiplet could be located. A systematic manner of doublet splitting is found for the lowest states with main configuration . A new decay branch of the single-particle state is attributed to an admixture of quadrupole core vibration. 相似文献
16.
Laser-induced fluorescence excitation has been used to measure Stark splittings of selected lines in the and band systems of H2CS in electric fields up to 13 kV/cm. The derived excited state a-axis dipole moments are 0.820 ± 0.007 D for the 41 level of the 1A2 state; 0.838 ± 0.008 D for the zeroth vibrational level of 1A2; and 0.534 ± 0.015 D for the zeroth vibrational level of the 3A2 state. These results are compared with the corresponding values of H2CO, and interpreted in terms of the changing localization of the π and orbitals accompanying electronic excitation. 相似文献
17.
H.D. Bist J.C.D. Brand A.R. Hoy V.T. Jones R.J. Pirkle 《Journal of Molecular Spectroscopy》1977,66(3):411-420
The band system of NO2, , has been measured in absorption in a neon matrix at 6 K, using 15NO2 and N18O2 in addition to the normal isotope. The spectrum consists essentially of a single, long progression of bands terminating on successive levels of the bending mode in the upper state. Transitions to odd- and even-v2′ states occur with a uniform intensity distribution indicating that the rotation of the bent ground state of NO2 about its near-prolate axis is hindered in the matrix. The observations strongly suggest that the top axis of the molecule coincides with a C2 axis of neon crystals in the polycrystalline matrix. Relative to the vapor absorption the matrix spectrum is red shifted by about 150 cm?1, the crystal field parameter V2 and principal constants of the state of 14N16O2 in neon being 相似文献
18.
The electronic absorption spectrum of cyanogen chloride has been investigated in the range 2200-1250 Å. The first s-Rydberg transitions, and have been assigned, and analyzed to yield exchange and spin-orbit coupling parameters. The relative intensities of these two transitions have been shown to accord with an intermediate coupling situation. The intravalence excitations, leading to 1.3(Σ?, Δ and Σ+) states, have been discussed. It has been shown that one or both of the 1Σ? and 1Δ states have bent geometries and that the 1Σ+ state is located (tentatively) at 79 755 cm?1. Two states have been assigned, one at 56 340 cm?1, the other at 74 450 cm?1. The latter assignment is tentative, being largely based on observed vibronic interferences between the transition and the 74 450 cm?1 transition. A considerable amount of vibrational oscillator strength and quantum defect data is presented. 相似文献
19.
Robert S. Mulliken 《Journal of Molecular Spectroscopy》1976,61(1):92-99
Predissociations in the y1Πg and Rydberg states of N2 (configurations and , respectively) and their likely causes, are discussed. Peaking of rotational intensity at unusually low J values, without sharp breaking off, is interpreted as due to case c? or case ci predissociation. Λ doubling in the y state, attributed to interactions with the state and with another, 1Σ+, state of the same electron configuration as x, is analyzed. From this analysis the location of the (unobserved) state, here labeled x′, is obtained. It is concluded that the predissociation in the Π+ levels of the y state is an indirect one mediated by the interaction with x′ coupled with predissociation of x′ by a state dissociating to atoms: combined, however, with perturbation of the y state by the k1Πg Rydberg state (configuration ), whose Π+ levels are completely predissociated. 相似文献
20.
Robert W. Field Richard A. Gottscho E. Miescher 《Journal of Molecular Spectroscopy》1975,58(3):394-413
No perturbation between two valence states of NO has ever been identified, although many valence-Rydberg and several Rydberg-Rydberg perturbations have been extensively studied. The first valence-valence crossing to be experimentally documented for NO is reported here and occurs between the 15N18O B2Π (v = 18) and B′2Δ (v = 1) levels. No level shifts larger than the detection limit of 0.1 cm?1 are observed at the crossings near and ; two crossings involving higher rotational levels could not be examined. Semi-empirical calculations of spin-orbit and Coriolis perturbation matrix elements indicate that although the electronic part of the interaction is large, a small vibrational factor renders the 15N18O B (v = 18) ? B′ (v = 1) perturbation unobservable. Semi-empirical estimates are given for all perturbation matrix elements of the operators and which connect states belonging to the configurations , , and . 相似文献