Premium
Time‐Resolved Fluence Studies and Delayed Ionization of the Niobium‐Carbon Cluster System
Author(s) -
Stairs Jason R.,
Peppernick Samuel J.,
Davis Kevin M.,
Castleman A. Welford
Publication year - 2004
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1560/xh55-0a98-b2c4-grql
Subject(s) - ionization , chemistry , fluence , microsecond , atomic physics , nanosecond , atmospheric pressure laser ionization , cluster (spacecraft) , laser , ionization energy , photoionization , excimer laser , ion , optics , physics , programming language , organic chemistry , computer science
The effect of laser fluence on the process of delayed ionization in niobium‐carbon clusters is studied over the range of 1.25 × 10 4 to 9.175 × 10 4 W/cm 2 (3.7 mJ/pulse to 0.5 mJ/pulse) with a 308‐nm XeCl Excimer laser. Delayed ionization has been observed in some cluster systems where the ionization energy of the cluster is lower than its binding energy. This characteristic allows the cluster to act as its own heat bath in which the ionization energy can be stored in the vibrational modes. Through multiphoton excitation via a nanosecond‐pulsed laser, an electron is ejected on the microsecond timescale. Fluence studies were performed in order to measure the degree of multiphoton ionization that occurs during delayed ionization. A new data analysis technique, referred to as a “time‐resolved fluence study”, is presented which demonstrates the ability of clusters differing in size to store various amounts of vibrational energy.