New interpretation of proton and deuteron tunneling in 2'-methylacetophenone

This is the accepted manuscript of the following article: Fernández-Ramos, A., Siebrand, W., & Smedarchina, Z. (2013). New interpretation of proton and deuteron tunneling in 2'-methylacetophenone. Chemical Physics Letters, 586, 61-66. doi: 10.1016/j.cplett.2013.09.020The enol–keto transition rate constants in 2′-methylacetophenone observed by Grellmann et al. are calculated from first principles. The results reinterpret the proposed mechanism and show that proton tunneling is preceded by dissociation of a substrate-solvent complex rather than by rotamer interconversionS

The rainbow instanton method: A new approach to tunneling splitting in polyatomics

The following article appeared in The Journal of Chemical Physics 137, 224105 (2012) and may be found at https://doi.org/10.1063/1.4769198A new instanton approach is reported to tunneling at zero-temperature in multidimensional (MD) systems in which a “light particle” is transferred between two equivalent “heavy” sites. The method is based on two concepts. The first is that an adequate MD potential energy surface can be generated from input of the stationary configurations only, by choosing as a basis the normal modes of the transition state. It takes the form of a double-minimum potential along the mode with imaginary frequency and coupling terms to the remaining (harmonic) oscillators. Standard integrating out of the oscillators gives rise to an effective 1D instanton problem for the adiabatic potential, but requires evaluation of a nonlocal term in the Euclidean action, governed by exponential (memory) kernels. The second concept is that this nonlocal action can be treated as a “perturbation,” for which a new approximate instanton solution is derived, termed the “rainbow” solution. Key to the approach is avoidance of approximations to the exponential kernels, which is made possible by a remarkable conversion property of the rainbow solution. This leads to a new approximation scheme for direct evaluation of the Euclidean action, which avoids the time-consuming search of the exact instanton trajectory. This “rainbow approximation” can handle coupling to modes that cover a wide range of frequencies and bridge the gap between the adiabatic and sudden approximations. It suffers far fewer restrictions than these conventional approximations and is proving particularly effective for systems with strong coupling, such as proton transfer in hydrogen bonds. Comparison with the known exact instanton action in two-dimensional models and application to zero-level tunneling splittings in two isotopomers of malonaldehyde are presented to show the accuracy and efficiency of the approachS

Multidimensional Hamiltonian for tunneling with position-dependent mass

A multidimensional Hamiltonian for tunneling is formulated, based on the mode with imaginary frequency of the transition state as a reaction coordinate. To prepare it for diagonalization, it is transformed into a lower-dimension Hamiltonian by incorporating modes that move faster than the tunneling into a coordinate-dependent kinetic energy operator, for which a Hermitian form is chosen and tested for stability of the eigenvalues. After transformation to a three-dimensional form, which includes two normal modes strongly coupled to the tunneling mode, this Hamiltonian is diagonalized in terms of a basis set of harmonic oscillator functions centered at the transition state. This involves a sparse matrix which is easily partially diagonalized to yield tunneling splittings for the zero-point level and the two fundamental levels of the coupled modes. The method is tested on the well-known benchmark molecule malonaldehyde and a deuterium isotopomer, for which these splittings have been measured. Satisfactory agreement with experiment results is obtainedS

Participatory forest management in conflict situations

During the last decades natural resource management in general and forest management in particular have changed. In the past forests were managed for a single commodity and for the general public, but lately more and more emphasis has been put on the multi-functionality of forests. Thus it has been recognized that multiple interests are connected to forests and that the general public in fact consists of a variety of stakeholders. The interests connected to forests are often incompatible and sometimes conflicts arise over them. Participation, the involvement of stakeholders into a decision-making process, has been suggested to be a suitable approach to manage multiple interests and to avoid the escalation of conflicts in many cases. The changing of natural resource management has manifested itself in international forest policy in which participation has received considerable attention. Also in Sweden forest management has changed over the past decades; in the 1980s and 1990s conservation issues became incorporated in forest management and recently also social values have become a part of the objectives of Swedish forest policy. Participation also has gained importance; in 2005 Sweden ratified the Århus Convention in which participation has a central place. Participation may be an approach to deals with the multiple interest and the returning conflicts in the mountainous forest regions. The regions have been inhabited by the Sámi since ancient times. These indigenous people have the ancient right to live on these lands and herd their reindeer. Besides multiple interests there thus also exists a dilemma of overlapping rights. The objective of this study was to to implement a stakeholder and interest analysis, and on the basis of it acquire knowledge about participation in forest management in the mountainous forest regions of Sweden. A case study was executed around the planning of clear-cuts in a 500 ha mountain forest in Swedish Lapland (Stöken). Multiple rights, interests and stakeholders are connected to the planning in Stöken. Two forests owner associations have the right to harvest timber and the Sámi have the right to graze their reindeer on the same land. Beside that, Stöken is located on the opposite shore of a very important cultural heritage site and has high nature values. The two main techniques used during this case study are semi-structured interviews and document analyses. Eight representatives were interviewed. On the basis of the interviews the interests that are connected to the planning in Stöken were identified, as well as the stakeholders that should represent these interests. Insight was also gained in how these interests relate to each other and how they are competitive. Together with the analysis of special forestry plans that include nature and social values the interviews gave insight in how participation is currently practiced. Most importantly the respondents were asked on which level of influence the different stakeholders should be able to participate in forestry planning in the future. Seven interests appeared to play an important role in the planning in Stöken: cultural heritage, local inhabitancy, reindeer husbandry, large-scale forestry, recreation and tourism, ownership of adjacent land, and environmental and nature values. These interests are all to some extent competitive with forestry. Some interests are besides that competitive with each other. Participation currently only consists of consultation with the involved Sámi Community. Such consultations are required by law and have a formal character. They often take place behind closed doors. The main findings of this study are that stakeholders should be informed about felling plans from the very beginning, but that providing information is not enough and stakeholders should be actually involved in planning processes, preferably on the levels of influence of advisory body or cooperation. The conclusion of this study is that in addition to the circumstances in mountainous forest areas (multiple right, interests and stakeholders, and escalation of conflicts) and the stimulation of participation in national and international forest policy, participation is wanted by the stakeholders themselves

Methanol dimer formation drastically enhances hydrogen abstraction from methanol by OH at low temperature

The kinetics of the reaction of methanol with hydroxyl radicals is revisited in light of the reported new kinetic data, measured in cold expansion beams. The rate constants exhibit an approximately 102-fold increase when the temperature decreases from 200 to 50 K, a result that cannot be fully explained by tunneling, as we confirm by new calculations. These calculations also show that methanol dimers are much more reactive to hydroxyl than monomers and imply that a dimer concentration of about 30% of the equilibrium concentration can account quantitatively for the observed rates. The assumed presence of dimers is supported by the observation of cluster formation in these and other cold beams of molecules subject to hydrogen bonding. The calculations imply an important caveat with respect to the use of cold expansion beams for the study of interstellar chemistryA. F. R. and E. M. N. acknowledge funding from Ministerio de Economia y Competitividad of Spain (Research Grant No CTQ2014-58617-R). E. M. N. acknowledges financial support from Xunta de Galicia (Research Grant No GRC2014/032)S

Mind the Relationship: A Multi-Layered Ethical Framework for Citizen Science in Health

There is a heated debate about what citizen science is and is not. We argue that instead of aiming at a definition of citizen science, we should reflect upon its ethical starting points. Based on our practical experiences with citizen science initiatives, we come up with an ethical framework that consists of two core values (respect and justice), five ethical desiderata (relationship between equals; recognition of each other's capacities, knowledge, and agency; reciprocity; openness for different goals; and openness for different research methods and paradigms) and two fundamental qualities (symmetry and transparency). The desiderata reflect ethically problematic practices, such as the use of citizens by academic scientists as mere sensors, and biases in the existing literature, such as labelling the projects that are initiated and led by citizens as “extreme”. The desiderata are supported by two ethical theories: care ethics and the capabilities approach. The aim of our ethical framework is to stimulate and facilitate reflection upon what needs to be considered when co-creating or assessing a citizen science initiative. Fundamentally, citizen science ought to be a humanizing endeavour unlocking the investigative capacities of humans. The ethical framework is meant to help reflect on this endeavour.</p