Effect of field-ionization dynamics on time-of-flight mass spectra

✍ Scribed by J.L. Persson; R.L. Whetten

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 445 KB
• Volume: 147
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(88)85077-2

✦ Synopsis

Ion time-of-flight lineshapes are found to be drastically altered by the process of tunneling field ionization in the case of nearthreshold photoionization. The delay-time distributions observed correspond directly to the times for tunneling through the fieldionization barrier. Using this effect, field ionization rates can be precisely measured over a wide dynamic range by high-resolution mass spectrometry. Results for threshold ionization of the Al atom in fields of 5-500 V/cm and mean decay time of 0.02 to 20 us are presented to illustrate the decay profiles and threshold shifts observed. The latter values can be explained using the concept of the classical barrier to field ionization.