摘要:

Oriented crystal growth on an amorphous substrate has been achieved using an artificially created surface‐relief grating. Crystallites of KCl grown from a water solution onto a 320‐nm spatial‐period square‐wave grating in SiO2nucleated preferentially at vertical steps and grew with ⟨100⟩ directions parallel to the grating axis. It is proposed that artificially created surface microstructures may provide a new means of manipulating the growth and orientation of crystalline overlayers.

ISSN:0003-6951    

DOI:10.1063/1.90054

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

We have made an absolute determination of the electron attachment coefficient &eegr; (cm−1) in helium containing 0.1–1% fluorine covering anE/Nrange from 3Td–17Td. At an estimated average energy of 5 eV we find a rate coefficient equal to (7.5±1.5) ×10−10cm3/sec.

ISSN:0003-6951    

DOI:10.1063/1.90055

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Space‐charge effects of beamlet‐beamlet interaction in the unneutralized accelerator region of intense ion sources have been computed. If shielding effects of the electrodes are neglected, the radial space charge of a typical ion source is so great that most of the beam will hit the second electrode or will undergo nonlinear steering. Beam divergence will be an order of magnitude larger than that expected from considerations of spherical aberrations of a single beamlet caused by deviations from Pierce geometry. If shielding effects of the electrodes are sufficiently great that only nearest‐neighbor beamlet‐beamlet interactions are important, then the outermost beamlets (or those near a water line) will cause a total beam divergence which is the same order of magnitude as that due to single‐beamlet spherical aberrations, and far more than the divergence expected from source ion temperature. A solution to this problem is proposed.

ISSN:0003-6951    

DOI:10.1063/1.90056

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Rates for the recombination processesX+2+F−+X→[X2F]*+X, (X≡He,Ne,Ar,Kr,Xe) are calculated at 300 K for pressures of the background gasXup to 50 atm. We find rates as high as (2–6) ×10−6cm3 sec−1for pressures of 1–8 atm as the gas is varied from Xe to He. The rates are somewhat smaller than those for the corresponding cases involving atomic ions.

ISSN:0003-6951    

DOI:10.1063/1.90057

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Time‐resolved and time‐integrated spectra for Ar‐F2mixtures excited by proton beams with various F2pressures are obtained to determine the lifetime of Ar2F*. The quenching rate constant of Ar2F* by F2is also reported.

ISSN:0003-6951    

DOI:10.1063/1.90058

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

High‐repetition‐rate (500 pps) laser action in XeF molecules at 351 and 353 nm in a gas mixture of He, Xe, and NF3has been demonstrated by use of a blowdown‐type fast‐flow system and thyratron‐switched high‐repetition‐rate pulse generators. The transverse‐flow velocity was 14 m/sec across a discharge region of 1×0.4×30 cm at a pressure of 650 Torr. The electric discharge pulse width was 60 nsec. For single‐shot operation, laser output energy of 6 mJ/pulse and electric efficiency of 0.25% have been obtained. For high‐repetition‐rate operation, the output energy per pulse was only 3 mJ as a result of the long charging time constant.

ISSN:0003-6951    

DOI:10.1063/1.90059

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

An HCl laser that uses isotopic V‐V energy transfer collisions as a pumping mechanism has been demonstrated. This multiline laser, which utilized an intracavity cold gas isotope filter, increased the energy from theP1lines of H37Cl while decreasing the energies of theP1andP2lines of H35Cl. Previously unreported lines, including emission fromR‐branch transitions, have also been observed from single‐line HCl and HBr lasers.

ISSN:0003-6951    

DOI:10.1063/1.90060

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Voltage‐tunable far‐infrared emission was observed fromn‐channel Si‐MOSFET’s on high‐index surfaces. The emission results from radiative decay of electronic excitations across a minigap in the ground‐state subband of the channel. We have observed emission of 10−9W at 4.4 meV with a linewidth of ∼1 meV. Our results indicate that a voltage‐tunable monochromatic source of several times 10−7W and tuning from ∼1 to ∼20 meV is attainable.

ISSN:0003-6951    

DOI:10.1063/1.90047

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Substantial difference‐ and sum‐frequency signals (up to 10−7W) have been generated and reradiated by mixing the HCN laser radiation at 337 &mgr;m with that of a (tunable) millimeter‐wave klystron in a metal‐semiconductor point‐contact or Schottky barrier diode. The magnitude and degree of monochromaticity of the generated power were sufficient for high‐resolution spectroscopy as verified by measurements on H2S and CH3OH.

ISSN:0003-6951    

DOI:10.1063/1.90048

出版商:AIP    

年代:1978

数据来源: AIP

摘要:

Optical surface waves propagating along the surface of a multilayer stack have been observed. The multilayer stack is grown by liquid phase epitaxy. The transverse intensity distribution measured is found to agree with our theoretical calculation.

ISSN:0003-6951    

DOI:10.1063/1.90049

出版商:AIP    

年代:1978

数据来源: AIP