The proton dynamics of poly(4-hydroxystyrene) (PHS) films were investigated using Coumarin 6 (C6). The acid density was 0.022 nm À3 at the exposure dose of 10 mC cm À2 (75 keV electron beam). The absorption intensity of C6 proton adducts was saturated at a certain concentration of C6, indicating an almost complete addition of protons at this C6 concentration. Protons can move in PHS films near C6 molecules even at room temperature. Also, the absorbed dose was estimated using 60 Corays. The acid yield can be well explained by an acid generation model involving the ionization of a base polymer.

The quantum defect method, generalised to the spin-orbit coupling scheme, has been used to calculate the oscillator strengths of the principal series for atomic caesium, taking into account the core polarisation produced by the valence electron. The good agreement obtained with respect to experimentally measured values has led us to carry out new calculations of generalised two-photon ionisation cross sections for the atomic caesium 6s ground state with linearly and circularly polarised incident radiation in the deep minimum region, related to destructive interferences, near the intermediate 7P resonance. A theoretical method previously developed was used; excellent agreement was obtained with respect to recent experimental data. The degree of spin polarisation of the ejected electrons has been calculated in the same region of incident photon energy.

Laser-induced and matrix-free desorption/ionization on various submicrometer structures was investigated. First, to examine the effect of surface roughness on ionization, a silicon wafer or stainless steel was scratched with sandpaper. The fluences of a 337-nm nitrogen laser, required for ionization of synthetic polymers and reserpine, were markedly reduced on the scratched stainless steel or silicon as compared to the corresponding untreated surface. Next, arrays of submicrometer grooves, which had been lithographically fabricated on a silicon wafer, yielded protonated angiotensin, and the morphologic orientation demonstrated the positive relation between the laser and groove directions for promoting ionization. The fabricated structure also suggested the submicrometer, but not smaller, or nanometer, structures to be a key factor in direct desorption/ionization on rough surfaces. Finally, submicrometer porous structures of alumina or polyethylene yielded intense molecular ion signals of angiotensin and insulin, in response to direct UV irradiation, when the surface was coated with Au or Pt. The coating provided the additional advantage of prolonged activity for a porous alumina chip, exceeding a month even when the chip was left in the open air. These results indicate that laser-induced desorption/ionization of organic compounds can be implemented on submicrometer structures with an Au- or Pt-coated surface irrespective of the basal materials.

Dependence of acid generation efficiency on the protection ratio of hydroxyl groups in chemically amplified electron beam, x-ray and EUV resists Acid-related matters are a critical issue in a chemically amplified resist, in which photo-or radiation ͑ionizing radiation͒-generated acids drive pattern formation reactions in exposed areas. The photosensitization of resist materials has been formulated by Dill et al. ͓IEEE Trans. Electron. Dev. 22, 445 ͑1975͔͒. The applicability of the formulation by Dill et al. to acid generation in chemically amplified photoresists has been proven by many researchers. The acid yields in photoresists are predicted well by the formulation of Dill et al. However, the formulation of Dill et al. cannot be applied to chemically amplified resists for ionizing radiation such as electron beams and extreme ultraviolet rays because polymer ionization significantly contributes to acid generation in these resists. In this study, the authors formulated acid generation in a chemically amplified resist for ionizing radiation. By the analysis of the dependence of acid yield on acid generator concentration, the details of acid generation paths were clarified.