Dipole-allowed transitions in collisions of charged particles and Na(30s) Rydberg atoms: Method of virtual quanta in low velocity collisions
- Univ. of Kentucky, Lexington, KY (United States)
Experimental studies of the depopulation of Na(30s) Rydberg atoms under charged-particle bombardment have been undertaken to identify the range of collision velocities at which the coupling behavior of the 30s state to nearby levels changes from predominantly non-dipole allowed at low velocity to dipole-allowed coupling at high velocity. Measurements carried out in this laboratory, involving H{sup +}, H{sub 2}{sup +}, He{sup +}, and e{sup {minus}} projectiles incident on Na(30s), cover the reduced projectile velocity range (v{sub r}) from 1.7 to 200 times the mean orbital velocity of the excited 30s electron. The ratio of the sum of the cross sections for the dipole-allowed transitions (30s to 30p and 30s to 29p) to the total depopulation cross section was found to increase from only 20% at v{sub r} = 2.4 to over 95% at v{sub r} {ge} 10. Absolute cross sections for the dipole-allowed 30s to 30p transition have also been measured and exhibit an unexpected projectile-velocity dependent threshold. The Weizsicker-Williams Method of Virtual Quanta has been extended to include low projectile velocities and is found to be in good agreement with the observed projectile-velocity dependence of both dipole and non-dipole allowed transitions in Na(30s).
- OSTI ID:
- 199758
- Report Number(s):
- CONF-941129--; CNN: Grant PHY-9122377
- Country of Publication:
- United States
- Language:
- English
Similar Records
Electron-collision induced dipole transitions in Na Rydberg Atoms: 30s-30p and 30s-29p absolute cross sections
Multilevel effects on the balance of dipole-allowed to dipole-forbidden transitions in Rydberg atoms induced by a dipole interaction with slow charged projectiles