Engineering topics

Chiang, C. C.

Publications and source records attributed to Chiang, C. C..

3 records

DOE OSTI2020

Pure spin current phenomena

Spintronic phenomena and devices have evolved from exploiting spin-polarized current to pure spin current. A pure spin current can more efficiently deliver spin angular momentum with fewer or no charge carriers, enabling spin–orbit torque switching in ferromagnets. The prospects of antiferromagnetic spintronics, especially electrical switching, remain perplexing and controversial. Here, we describe some recent advances, outstanding issues, challenges, and prospects of pure spin current.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

NASA NTRS1983

Fluorescence yield from photodissociation of CH4 at 1060-1420 A

The photoabsorption and fluorescence cross sections of CH4 were measured using synchrotron radiation at 1060-1420 A. The fluorescence starts to appear at 1330 A, and its cross section increases with decreasing photon wavelengths. The fluorescence cross section at 1060 A is 0.38 x 10 to the -18th sq cm, which is much smaller than the theoretical expectation. It is unlikely that the CH2 production from CH4 photodissociation will have a population inversion in the singlet system. A vibrational structure observed at 1060-1120 A is probably the 1t2-3p Rydberg transition of CH4.

Lee, L. C.↗

NASA NTRS1982

Fluorescence yields from photodissociation of OCS at 1060-1240 A

The cross sections for the production of fluorescence (3000-8000 A) from excited photofragments of OCS were determined in order to gain a better understanding of the role of carbonyl sulfide in interstellar photochemistry. Synchrotron radiation was used as the light source for the measurements in the 1060-1240 A region, as it is suitable for measuring the absorption cross section in the structured region. It was found that the quantum yields for the production of various CO triplet states are less than 1.5% at the observed excitation photon wavelengths.

Lee, L. C.↗