Theoretical spectroscopy: Full quantum dynamical study of the vibrational structure of hydrated hydroxide

In many processes, the impact of nuclear quantum phenomena cannot be neglected if a physically correct simulation is aimed for [1]. This quantum description of the nuclear motion is usually obtained by mapping the system onto a grid, thus implying a discretisation of the configuration space. As a consequence, all quantities take the form of high-order tensors. Unfortunately, multidimensional representations imply an exponential scaling of data and the concomitant number of operations with system size as well as the difficulty of computing multidimensional integrals [2]. Solutions to these issues, in particular when considering the representation of the potential energy surface, exist in the form of tensor-decomposition schemes. We present the recently developed the Multigrid POTFIT (MGPF) algorithm [3] which alleviates the exponential scaling by avoiding the calculations on the full grid. Moreover, we introduceour latest improvements to the algorithm which provide numerical stability and higher accuracy through the use of non-product grids for combined modes [4]. We illustrate the power of the MGPF algorithm in conjunction with the Multiconfiguration Time-Dependent Hartree (MCTDH) method in the case of the full-dimensional (9D) study of the vibrational structure [5] and the computation of the infrared spectrum [6] of the hydrated hydroxide complex (H3O2-). [1] Fabien Gatti (Ed.) in Molecular Quantum Dynamics From Theory to Applications. Springer (2014). [2] H.-D. Meyer, F. Gatti, G. A. Worth (Eds.) Multidimensional Quantum Dynamics: MCTDH Theory and Applications, Wiley (2009). [3] D. Peláez, H.D. Meyer, The multigrid POTFIT (MGPF) method: Grid representations of potentials for quantum dynamics of large systems, J. Chem. Phys., 138, 014108 (2013). [4] D. Peláez, H.D. Meyer (in preparation) [5] D. Peláez, K. Sadri, H.-D. Meyer, Full-dimensional MCTDH/MGPF study of the ground and lowest lying vibrational states of the bihydroxide complex, Spectrochimica Acta Part A,119, 42 (2014). [6] D. Peláez, H.D. Meyer, On the infrared absorption spectrum of the hydrated hydroxide (H3O2-) cluster anion, Chem. Phys., (in press) (2016).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Evaluating the Role of Intermolecular Interactions in pi-conjugated Materials: What can we learn from DFT calculations and Raman Spectroscopy

For practical applications in sensors, dynamic covalent chemistry and molecular (photochromic) switches, soft conjugated materials can be envisaged as promising functional materials.1 To advance in this research field, deciphering the mechanisms involved on how sensitive the structural and electronic properties are to specific molecular ordering is essential. In stimuli responsive materials, such as piezochromic materials, the molecular orientation and intermolecular interactions can change upon mechanical grinding. In this context, Raman spectroscopy can help to clarify how organic molecular solids respond to high pressure, for instance, by reducing intermolecular interactions and/or changing molecular conformations. On the other hand, DFT calculations can help us to rationalize the nature and stability of the formation of aggregates and complexes, allowing the evaluation of the effects of the surrounding media on different molecular properties.3 Thus, we propose here a combined Raman spectroscopy and DFT study of molecular crystals and/or aggregates upon soft external stimuli that can be envisaged as a very sensitive approach to understand the structural effects causing any chromic changes. To this end, we focus on different families of conjugated materials with potential application in organic electronics, ranging from cyclophane aggregates to tetrathiazolylthiophenes crystals (Figure 1).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Impact of the Intermolecular Interactions on the Electronic and Charge-Transport Properties of Organic Materials: A Joint Experimental and Theoretical Approach

The use of organic materials to design electronic devices has actually presented a broad interest because they constitute an ecological and suitable resource for our current "electronic world". These materials provide several advantages (low cost, light weight, good flexibility and solubility to be easily printed) that cannot be afforded with silicon.[1] They can also potentially interact with biological systems, something impossible with inorganic devices. The performance of the organic-based electronic devices critically depends not only to the intrinsic properties of the conjugated cores but also to the supramolecular arrangement.[2] In this contribution, we present some of our more recent investigations on this field dealing with the better understanding of the complex structure-properties relationships of organic nanomaterials.[3] For this purpose, we use a joint experimental and theoretical approach that includes spectroscopic measurements and molecular modeling.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Multiresponsive chromic soft materials: formation of macrocycles from carbazole-based biradicaloids

-conjugated biradical compounds become essential building blocks in DCC (dynamic covalent chemistry).1 This field is based on the creation of structural scaffolds based on chemical components which interact through strong but reversible bonds. Importantly, dynamic covalent bonds will be at the center of attention because of their unique feature to become reversible under mild conditions.2 Recently, we have demonstrated the reversible interconversion between a stable quinoid precursor based on a para-substituted carbazole with terminal dicyanomethylene groups and a macrocycle cyclophane upon soft external stimuli (temperature, pressure, light), which results on strong chromic features.3 In this work, we investigate the interconversion of the monomer/cyclophane transformation in carbazole-based systems, both in solution and solid state, upon external stimuli. To this end, we use a combined experimental and theoretical study that links vibrational spectroscopy (Raman and IR) with DFT calculations.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Carbazole-based biradicaloids as potential building blocks for dynamic covalent chemistry

Pi-conjugated biradical compounds become essential building blocks in DCC (dynamic covalent chemistry).1 This field is based on the creation of structural scaffolds based on chemical components which interact through strong but reversible bonds. Importantly, dynamic covalent bonds will be at the center of attention because of their unique feature to become reversible under mild conditions.2 Recently, we have demonstrated the reversible interconversion between a stable quinoid precursor based on a para-substituted carbazole with terminal dicyanomethylene groups and a macrocycle cyclophane upon soft external stimuli (temperature, pressure, light), which results on strong chromic features.3 In this work, we investigate the impact of the substitution pattern (i.e., the insertion of dicyanomethylene groups at the 2,7 (para) or 3,6 (meta) positions or the elongation of the carbazole backbone) on the formation of stimuli-responsive cyclophanes by self-assembly. To this end, we use a combined experimental and theoretical study that links vibrational spectroscopy (Raman and IR) with DFT calculations.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Asylum, Credible Fear Tests, and Colonial Violence

A credible fear test is an in-depth interview process given to undocumented people of any age arriving at a U.S. port of entry to determine qualification for asylum-seeking. Credible fear tests as a typical immigration procedure demonstrate not only what structural epistemic violence looks like but also how this violence lives in and through the design of asylum policy. Key terms of credible fear tests such as “significant possibility,” “evidence,” “consistency,” and “credibility” can never be neutral in the context of colonial administrative violence. We argue that these terms function as mechanisms of exclusion and demonstrate that the capacity to be violent (i.e. to be an instrument of violence) is built into these tests, ready to be deployed when an administration wants to stop certain people from certain places from entering without regard to their own ongoing occupation of Indigenous lands. Not only are such practices instruments of violence, but the concept of ‘violence’ continues to be organized, defined, and conceived within settler colonial epistemologies so as to exclude these administrative forms of violence deployed against Indigenous peoples and people of color from recognition and nameability. We argue that this is an intentional strategy of colonial power preservation that is functionalized through social processes that remain structurally stable and self-regenerating across historical and political changes

The gender of representation: On democracy, equality, and parity

The debate regarding the statutory introduction of gender parity in electoral lists has been led, on the one hand, by those who envisage parity as a way to attain substantive equality between the genders. The opposition has been led by those who, on the other hand, reject it as going against the very principle of equality in its formal dimension, as well as against the autonomy of political parties. Based on the experience of France and Italy on this matter, this article discusses both sets of arguments and applies them to the Spanish context. It further defends the need to bypass the theoretical parameters of equality and affi rmative action in order to place the defense of electoral parity within the theoretical parameters of the postliberal democratic state. It aims, therefore, at articulating electoral parity as a conceptual requisite of the democratic state