[1] It is well known that skeletal remains of carbonate secreting organisms can provide a wealth of information about past environments. Sr/Ca ratios have been successfully used as a temperature proxy in corals and sclerosponges. Previous work on aragonitic bivalve shells has not been conclusive but suggests a major control of growth rate on Sr/Ca ratios. As many studies have used bivalve growth rates to determine temperature, we tested if Sr/Ca ratios could predict temperature through its relationship with growth rate. Shells from the two species of clams from the same family (veneroidea) studied here, Saxidomus giganteus and Mercenaria mercenaria, show vastly different seasonal Sr/Ca profiles. A strong relationship between average annual Sr/Ca ratios and annual growth rate was found in S. giganteus shells from both Washington (R 2 = 0.87) and Alaska (R 2 = 0.64), USA, but not in M. mercenaria shells from North Carolina, USA. Furthermore, the Sr/Ca-growth rate relationship was also evident upon a more detailed inspection of subannual growth rates in S. giganteus (R 2 = 0.73). Although there were significant positive correlations between Sr/Ca ratios and temperature in S. giganteus shells, the correlations were weak (0.09 < R 2 < 0.27), and thus Sr/Ca ratios cannot be used as a reliable temperature proxy in these species of aragonitic bivalves. It is clear from this study that Sr/Ca ratios are not under thermodynamic control in either clam species, since thermodynamics predict a negative correlation between Sr/Ca ratios and temperature in aragonite. This points toward dominance of biological processes in the regulation of Sr 2+ . This is also reflected by the largely differing Sr/Ca partition coefficients (D Sr ) in these shells (D Sr % 0.25), when compared to inorganic, coral, and sclerosponge studies (D Sr % 1), all of which show a negative dependence of Sr/Ca on temperature. We suggest that caution be taken when using Sr/Ca in any biogenic aragonite as a temperature proxy when the D Sr greatly deviates from one, as this indicates the dominance of biological controls on Sr/Ca ratios.

Correlation of atomic force microscopy sidewall roughness measurements with scanning electron microscopy line-edge roughness measurements on chemically amplified resists exposed by x-ray lithography

1) is gratefully acknowledged.) for a particular interaction. Furthermore, isotropic and dipolar contributions to the hyperfine tensors can be distinguished. On the other hand, the difficulties associated with the analysis of the time-domain data are avoided by using ENDOR. Also the range of hyperfine and quadrupole interactions that can be measured with ENDOR is much broader than that currently accessible to the ESE technique.Abstract: Angle-resolved photoelectron spectra were obtained on a series of nitrogen-containing aromatic systems using synchrotron radiation as the ionizing source. The angular distribution parameter, 0, was measured in the photon energy range 12-27 eV for the first three orbitals of 2-fluoropyridine, pentafluoropyridine, and pyridine, and for the first four orbitals of pyrimidine and pyrazine. The angular distribution parameter as a function of photon energy is shown to be of value in the assignment of bands in photoelectron spectra and has been applied to the photoelectron spectra of pyridine. The fluoro-substituted pyridines provided information on the trend of the p values for nonbonding orbitals with predominant nitrogen lone-pair character. The diazines demonstrated that f? values as a function of photon energy could be used for orbital assignments even in the case of partial band overlap. For pyridine the overlap of the first two ionic levels, consisting of a R and a nonbonding orbital, is so severe that unambiguous assignment has been difficult but is now possible. Experimental evidence is presented for the sequence of these levels to be the nonbonding (n) orbital at lower ionization energy followed by the R orbital. The relevance of systematic investigations of the angle-resolved photoelectron spectroscopy of a homologous series of molecules as a function of photon energy is discussed.

We have measured the absolute fluorine atom concentrations in electron cyc!o!ron resonance (ECR! and reactive ion etching !ME) plasmas by optimizing the actinometry technique. The major difference between this work and conventional actinometry is that the Ar concentration measurements were pelformed by a residual gas analyser (RGA). The emission intensities of F (7037 A) and Ar (7504 A) were simultaneously measured by an optical multichannel analyser (OM) and the Ar concentration by a RGA. The F atom concentration at the wafer stage in the CF4 ECR plasma was measured to be (0.4 to 4)x1Ol2 ~m -~, the microwave power from 500 to 900 W, pressure from 0.5 (3.7 sccm) to 3.5 mTorr (58 sccm), and a fixed RF bias voltage of -50 V. The F atom concentration of the CF, ECR plasma was four times larger in the source region than in the downstream region. The F atom concentration of the CF4 RIE plasma for pressures from 13 to 62 mTorr was measured as (0.8 to 4 . 2 ) ~l O ' ~ ~m -~, for a CF4 flow rate of 20 sccm, and power inputs from 250 to 1500 W. The F atom concentration was larger in the RIE etcher than in the ECR etcher, but the F atom production efficiency was eight times larger in the ECR etcher than in the RE etcher for the same power level. In spite of the possibility of a factor two discrepancy in the measurements from absolute values because of the uncertainty in the absolute values of the cross sections, this technique provides a relatively simple and consistent reproducible measurement of F atom concentration to compare operation of the two types of etchers, which is reproducible to 110%.We further explored the actinometry for vacuum ultraviolet (vuv) emission region by using F (955 A) and Ar (1048 A). A similar trend of F atom concentration was found as for the visible actinometry, but the absolute value of fluorine atom concentration was typically 15% larger for the vuv actinometry.

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