In this paper the general question of laser-induced photochemistry on metal surfaces is addressed. Specifically, we have studied resonant photodecomposition of a variety of aromatic molecules on roughened silver surfaces in ultrahigh vacuum. A continuous ion laser source at a number of different wavelengths in the region 350-410 nm was used to produce graphitic carbon on the surface which was monitored by Raman spectroscopy at the 1580-cm"1 band of surface carbon. Laser power-dependence studies of fragmentation rate for several molecules at 406.7 nm indicate that the initial absorption step is a two-photon process. Energetic considerations imply that photochemistry for other molecules studied is also due to multiphoton absorption, except for benzaldehyde fragmentation with 350.7-nm excitation where the photodecomposition rate is linear in intensity. In this case photochemistry apparently occurs directly from the first excited singlet state following one-photon absorption. Distance-dependence studies of photofragmentation rates by use of an inert spacer layer to separate the molecule undergoing photochemistry from the surface indicate that energy transfer to the metal surface is important in determining the reaction rate. A maximum decomposition rate is observed for pyridine 15-20 Á from the surface, resulting from the different distance dependences of enhanced molecular absorption at rough silver surfaces and damping by energy transfer to the surfaces. These competing processes produce a maximum photochemical rate where surface-enhanced absorption is still present but the energy damping rate has decreased substantially. Intermediate species in the decomposition of pyridine and pyrazine to carbon have been observed as CN peaks in the surface Raman spectrum during photolysis of these molecules. The CN stretch frequency of these fragments is shifted from that observed for cyanide ions adsorbed on silver to a frequency typical of a nitrile such as C3H3N. The fragmentation mechanism for these and other surfaces adsorbed molecules studied remains to be established. Evidence indicates that radical formation is a likely pathway for some molecules (e.g., benzaldehyde) while other molecules may decompose through surface ionic species.

Why did Western Europe create uniquely strong international institutions in the 1950s, setting the foundations for today's quasi-federal European Union? This article contests explanations of the European Economic Community (EEC) as a straightforward response to structural interdependence, or as an institutionally “path-dependent” variation on such a response. Only leadership based on certain ideas explains why Europeans created the EEC rather than pursuing cooperation within weaker institutions or standard diplomatic instruments. In France—the only major state that insisted on the “community” framework—divided preferences and issue-linkages created “multiple equilibria” that allowed leaders to mobilize support for several European strategies. The EEC strategy was selected over viable alternatives by leaders who stood out from their party, bureaucratic, sectoral, and regional allies in holding certain ideas about Europe. This demonstration of the major, distinct impact of ideas offers concrete support to the growing theoretical literature on ideas and norms.

In recent years, a variety of efforts have been made in political science to enable, encourage, or require scholars to be more open and explicit about the bases of their empirical claims and, in turn, make those claims more readily evaluable by others. While qualitative scholars have long taken an interest in making their research open, reflexive, and systematic, the recent push for overarching transparency norms and requirements has provoked serious concern within qualitative research communities and raised fundamental questions about the meaning, value, costs, and intellectual relevance of transparency for qualitative inquiry. In this Perspectives Reflection, we crystallize the central findings of a three-year deliberative process—the Qualitative Transparency Deliberations (QTD)—involving hundreds of political scientists in a broad discussion of these issues. Following an overview of the process and the key insights that emerged, we present summaries of the QTD Working Groups’ final reports. Drawing on a series of public, online conversations that unfolded at www.qualtd.net, the reports unpack transparency’s promise, practicalities, risks, and limitations in relation to different qualitative methodologies, forms of evidence, and research contexts. Taken as a whole, these reports—the full versions of which can be found in the Supplementary Materials—offer practical guidance to scholars designing and implementing qualitative research, and to editors, reviewers, and funders seeking to develop criteria of evaluation that are appropriate—as understood by relevant research communities—to the forms of inquiry being assessed. We dedicate this Reflection to the memory of our coauthor and QTD working group leader Kendra Koivu.1

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Has European integration affected national electoral politics beyond the margins? Experts describe its main impact as empowerment of radical voices. Mainstream parties avoid European Union (EU) issues that divide their left-or right-based organizations; extreme parties attack the EU and the center’s silence. But EU issues also generate important dynamics inside mainstream parties. The authors theorize cross-cutting EU issues as an example of a general model of cross-issue interference. Two mechanisms of interference alter party strategizing. When electoral victories have strengthened leaders, cross-cutting issues produce muffling of more recently emerged issues. Divided parties cling to left—right issues and suppress fights over integration. But interference also runs the other way. When leadership is weak, muffling fails and challengers aggravate dissent. Internal fights on newer (EU) issues affect the selection of leadership on older (left—right) issues, generating displacement from electorally competitive positions. The authors document these mechanisms and their generality with mixed methods: pan-European panel analysis and interview-based accounts.