共查询到20条相似文献,搜索用时 15 毫秒
1.
Some experimental evidences for methane are produced that the simple transition from frequency scanning of nonlinear-optical resonances to magnetic one may be accompanied with transition from sub-Doppler collisionally broadened structure to sub-collision hyperfine one. It is conditioned by nonlinearity of splitting of hyperfine sublevel for molecules in the adiabatically varied magnetic field and, respectively, breaking the analogy of magnetic and frequency scannings. The exact calculation of the resonance structure is considered for molecules with only one spin subsystem. The approximately spin-additive calculation of the structure is given for sufficiently fast rotating molecules with greater number of spin subsystems. Within the same approximation an example of hyperfine doubling in the magnetic and electric spectra of nonlinear-optical resonance is considered for fluoromethane. 相似文献
2.
D. Porezag G. Jungnickel T. Frauenheim G. Seifert A. Ayuela M.R. Pederson 《Applied Physics A: Materials Science & Processing》1997,64(3):321-326
\chem{[C_{60}]_{\chemindex{n}}} -oligomers (, , and ) as well as dimers partially bridged by oxygen atoms or a group. The applicability of the scheme for finding the ground state of these systems was carefully checked against more sophisticated
methods including an all-electron, self-consistent (SCF) scheme based on the local-density-approximation (LDA), and the recently
developed generalized-gradient approximation (GGA). We present Raman intensities for the vibrations of the oligomers, obtained in the framework of the bond polarization model, and compare with recent experimental data.
Received: 26 September 1996/Accepted: 16 December 1996 相似文献
3.
B. Bodermann H. Knöckel E. Tiemann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,19(1):31-44
Based on new systematic high precision measurements of hyperfine splittings in different rovibrational bands of 127I2 in the near infrared spectral range between 778 nm and 816 nm, and the data in the range from 660 nm to 514 nm available
from literature, the quantum number dependence of the different hyperfine interaction parameters was reinvestigated. As detailed
as possible parameters were re-fitted from the reported hyperfine splittings in literature, considering that the interaction
parameters should vary smoothly with the vibrational and rotational quantum numbers, and follow appropriate physical models.
This type of consistency has not been sufficiently taken into account by other authors. To our knowledge it is now possible
for the first time to separate the hfs contributions of the two electronic states B
3
and X
1
Σ
+
g
for optical transitions in a very large wavelength range. New interpolation formulae could be derived for both states, describing
the quantum number dependences of the nuclear electric quadrupole, of the nuclear spin-rotation and also of the nuclear spin-spin
interactions. Using these new interpolation formulae the hyperfine splittings for the components with the quantum number condition
F
-
J
= 0 can be calculated with an uncertainty of ≤30 kHz for transitions in the wavelength range between 514 nm and 820 nm.
Received 17 July 2001 and Received in final form 17 October 2001 相似文献
4.
Received: 5 February 1998/Revised version: 18 March 1998 相似文献
5.
S. Urabe M. Watanabe H. Imajo K. Hayasaka U. Tanaka R. Ohmukai 《Applied physics. B, Lasers and optics》1998,67(2):223-227
1/2 -D5/2 electric-quadrupole-allowed transitions of a laser-cooled Ca+ ion in a small rf trap. The electron shelving method was used to measure the absorption spectrum of the electric-quadrupole-allowed
transitions, and the motional sidebands due to the secular motion of the ion in the harmonic potential well of the rf trap
were completely resolved. The effective temperature of the ion, estimated by comparing the observed sideband intensities with
the theoretical ones, was less than 4.4 mK. This result is in good agreement with that obtained from the analysis of the linewidth
measurement.
Received: 18 March 1998 相似文献
6.
C.A. Sackett C.C. Bradley M. Welling R.G. Hulet 《Applied physics. B, Lasers and optics》1997,65(4-5):433-440
7 Li has been studied in a magnetically trapped gas. Many-body quantum theory predicts that the occupation number of the condensate
is limited to about 1400 atoms because of the effectively attractive interactions between 7Li atoms. Using a versitile phase-contrast imaging technique, we experimentally observe the condensate number to be consistent
with this limit. We discuss our measurements, the current theoretical understanding of BEC in a gas with attractive interactions,
and future experiments we hope to perform.
Received: 4 June 1997 相似文献
7.
Bright atomic beam by a temporal Zeeman acceleration 总被引:1,自引:0,他引:1
Y. Fukuyama H. Kanou V.I. Balykin K. Shimizu 《Applied physics. B, Lasers and optics》2000,70(4):561-565
A novel method to produce a slow, monochromatic, and bright pulsed atomic beam from a magneto-optical trap by switching the
magnetic field of the trap is proposed. A pulsed lithium atomic beam with a brightness of 1.1×1015 /sr s and a velocity of 13 m/s was produced as an experimental proof of this technique. The conversion efficiency from the
trap into the atomic pulse was nearly 100%.
Received: 22 October 1999 / Revised version: 15 November 1999 / Published online: 8 March 2000 相似文献
8.
An ultrahigh resolution photoassociation spectrum of caesium atoms in a magneto-optical trap is presented. Hyperfine structure of the excited state molecule is obtained by using the lock-in method based on modulated cold atoms in this spectrum. Amplitude of resonant lines related to the rotational levels increases with photoassociation laser intensity, and saturation effect of photoassociation of cold atoms is observed in our experiment. The saturation intensity of photoassociation is deduced by fitting the experimental data to asaturation model based on scattering theory. Differences among saturation intensities of different rotational progressions in the υ=55 vibrational state of the caesium molecular long-range 0g- state have been found. 相似文献
9.
Atomic beam guide by a one-dimensional magneto-optical trap 总被引:1,自引:0,他引:1
An atomic beam has been collimated, compressed, and deflected simultaneously by an atomic beam guide based on an inclined
one-dimensional magneto-optical trap (1D-MOT). Isotope-selected rubidium atoms were extracted from the naturally-mixed thermal
atomic beam with this method. We could manipulate the transverse displacement of the deflected beam precisely by adjusting
the current in the copper rods to generate the quadrupole magnetic field. We could extract more than 50% of the incident atoms
as a deflection beam when we combined this deflection technique with the atomic deceleration using a broadband spectral light.
Received: 10 December 1998 / Published online: 24 June 1999 相似文献
10.
C. Raab J. Bolle H. Oberst J. Eschner F. Schmidt-Kaler R. Blatt 《Applied physics. B, Lasers and optics》1998,67(6):683-688
+ ions. Frequency doubling of a 100 mW diode laser at 986 nm results in up to 60 mW output power at 493 nm in a bandwidth of
less than 60 kHz with respect to the cavity used for locking. Reference frequencies of 18 spectral lines of Te2 near the 493 nm resonance of Ba+ have been measured using modulation transfer spectroscopy. The fluorescence excitation spectrum of a single Ba+ ion, measured with this laser, exhibits well-resolved dark resonances, which confirms the versatility of the system for quantum
optical experiments.
Received: 12 June 1998 相似文献
11.
D.-H. Lee Y. Yoon B. Kim J.Y. Lee Y.S. Yoo J.W. Hahn 《Applied physics. B, Lasers and optics》2002,74(4-5):435-440
A simple and reliable method is presented for optimizing the mode matching of a laser beam to the high-finesse cavity used
in pulsed cavity ringdown spectroscopy (CRDS). The method is based on minimizing the excitation of higher-order transverse
cavity modes through monitoring the non-degenerate transverse mode beating which becomes visible with induced cavity asymmetry
caused by slight misalignment. No additional instrument is required other than a pinhole aperture, thus this method can be
applied for CRDS experiments in the whole wavelength range. Measurements of the CRDS absorption spectrum of acetylene (C2H2) near 571 nm demonstrate that the mode-matching optimization improves the sensitivity of pulsed CRDS.
Received: 22 October 2001 / Revised version: 16 January 2002 / Published online: 14 March 2002 相似文献
12.
The hyperfine structure splittings of the P(10)14-1, R(15)14-1, and R(99)15-1 transitions at 585 nm, P(62)17-1 at 576 nm, and P(80)21-1 at 565 nm in 127I2 are measured by heterodyne spectroscopy using two dye lasers. In addition, the absolute frequencies of the hyperfine components P(10)14-1 a15 and P(80)21-1 a10 are determined using a self-referenced frequency comb. These frequencies are used in an experiment testing relativistic time dilation by laser spectroscopy on a fast ion beam. 相似文献
13.
Sven Thorwirth Michael C. McCarthy John B. Dudek Patrick Thaddeus 《Journal of Molecular Spectroscopy》2004,225(1):93-95
The carbon chain molecules vinylcyanoacetylene and cyanovinylacetylene have been investigated between 8 and 41 GHz by Fourier transform microwave spectroscopy of a supersonic molecular beam. Owing to the high spectral resolution of the present technique, significantly more accurate rotational and centrifugal distortion constants have been derived for both molecules. In addition, the dipole moments have been calculated at the B3LYP/cc-pVTZ level of theory. Because these carbon chains are similar in structure and composition to known astronomical molecules and because of their high polarity, both species are good candidates for radioastronomical detection. 相似文献
14.
K.W. Madison C.F. Bharucha P.R. Morrow S.R. Wilkinson Q. Niu B. Sundaram M.G. Raizen 《Applied physics. B, Lasers and optics》1997,65(6):693-700
Received: 8 July 1997 相似文献
15.
As a new method for measuring the spatial distribution of Bose–Einstein condensates, the magnetic resonance imaging (MRI)
method is proposed and studied in detail. The basic concepts, the resolution limit and the formalism of the MRI method are
presented. It is expected that a resolution higher than that in optical imaging methods can be obtained by using the MRI method.
Results of simulation of expected MRI signals for Bose–Einstein condensates containing dark solitons are also presented.
Received: 27 September 2001 / Revised version: 24 October 2001 / Published online: 17 January 2002 相似文献
16.
P. Rosenbusch J.A. Retter B.V. Hall E.A. Hinds F. Lison D. Haubrich D. Meschede 《Applied physics. B, Lasers and optics》2000,70(5):661-663
We have demonstrated that a cobalt single crystal can be used to make a remarkably smooth retro-reflector for cold paramagnetic
atoms. The crystal is cut so that its surface lies in the (0001) plane and the atoms are reflected by the magnetic field above
the surface due to the self-organized pattern of magnetic domains in the material. We find that the reflectivity for suitably
polarized atoms exceeds 90% and may well be unity. We use the angular spread of a reflected atom cloud to measure the roughness
of the mirror. We find that the angular variation of the equivalent hard reflecting surface is (3.1±0.3°)rms for atoms dropped
onto the mirror from a height of 2 cm.
Received: 29 November 1999 / Revised version: 24 February 2000 / Published online: 5 April 2000 相似文献
17.
M. Keller B. Lange K. Hayasaka W. Lange H. Walther 《Applied physics. B, Lasers and optics》2003,76(2):125-128
By combining the technologies of ion trapping and cavity QED, we have achieved deterministic coupling of single ions to an
optical field. By Doppler cooling, the spread of the ion’s wavepacket was reduced to 42 nm, corresponding to Lamb–Dicke localization.
As an application, we have measured the three-dimensional structure of cavity eigenmodes with sub-wavelength precision. The
setup presented is suited for the controlled coherent processing of atomic and photonic quantum information. Examples include
the triggered generation of single photons and two-ion quantum gates.
Received: 20 August 2002 / Revised version: 16 December 2002 / Published online: 26 February 2003
RID="*"
ID="*"Corresponding author. Fax: +49-89/32905-200, E-mail: keller@mpq.mpg.de 相似文献
18.
A. di Stefano D. Wilkowski J.H. Müller E. Arimondo 《Applied physics. B, Lasers and optics》1999,69(4):263-268
We have operated a magneto-optical trap and optical molasses for the laser cooling of cesium atoms on the basis of a five-beam
laser configuration. For the magneto-optical trap two laser beams counterpropagate along the axis of a quadrupole trap and
the remaining three beams propagate in the orthogonal plane at 120° to each other. The same optical configuration was used
for the optical molasses. We have tested the efficiency in atom collection and the temperatures reached in both cooling processes.
In comparison to previous results on a six-beam configuration, a lower number of atoms is collected, while comparable densities
are realized. The atomic temperatures have been measured through a delayed shadow-image technique, where one of the running-wave
cooling beams produces an absorptive image of the atoms on a camera.
Received: 14 January 1999 / revised version: 23 June 1999 / Published online: 8 September 1999 相似文献
19.
K. Toyoda H. Kataoka Y. Kai A. Miura M. Watanabe S. Urabe 《Applied physics. B, Lasers and optics》2001,72(3):327-330
Rare calcium isotope ions, 42Ca+ and 44Ca+, were efficiently separated from a laser-cooled ionic cloud in a linear Paul trap which was loaded from an atomic source
of a natural isotope mixture of calcium, in spite of their negligibly small abundances (0.647% and 2.086%, respectively) compared
with that of 40Ca (96.94%). Selective heating and cooling that arise from the isotope shifts were mainly used for the elimination of the
isotopes; selective heating and cooling enable flexible separation when combined with other mechanisms such as the inherent
mass selectivity of RF traps.
Received: 7 July 2000 / Published online: 10 January 2001 相似文献
20.
We theoretically investigated the mass dependence of the sympathetic cooling rate of gas-phase ions trapped in a linear radio-frequency-quadrupole
ion trap. Using an a priori molecular dynamical calculation, tracing numerically with Newtonian equations of motion, we found
that ions with a mass greater than 0.54±0.04 times that of the laser-cooled ions are sympathetically cooled; otherwise, they
are heated. To understand the mass dependence obtained using the molecular-dynamical calculation, we made a heat-exchange
model of sympathetic cooling, which shows that the factor of 0.54±0.04 is a consequence of absence of micro-motion along the
axis of the linear ion trap.
Received: 10 December 2001 / Revised version: 28 January 2002 / Published online: 14 March 2002 相似文献