Yes,More Decoherence: A Reply to Critics

Recently I published an article in this journal entitled “Less interpretation and more decoherence in quantum gravity and inflationary cosmology” (Crull in Found Phys 45(9):1019–1045, 2015). This article generated responses from three pairs of authors: Vassallo and Esfeld (Found Phys 45(12):1533–1536, 2015), Okon and Sudarsky (Found Phys 46(7):852–879, 2016) and Fortin and Lombardi (Found Phys, 2017). In what follows, I reply to the criticisms raised by these authors.     

Observer theories based on stueckelberg quations of motion

Stueckelberg dynamics is regarded as providing a basis for the construction of observer centered theories of particle motions. The approach involves the use of a generalized Jacobi principle to replace the four-dimensional dynamical theory of Stueckelberg by a four-dimensional geometrical theory, and then a three-dimensional dynamics is constructed from this. The causal difficulties encountered by Stueckelberg for curves which reverse direction in time appear to be absent in the present scheme.Our purpose has been to make more concrete, in a simple context, some of the ideas involved in the (conventional) causal framework recently constructed by us to deal with causal difficulties associated with hyperlight phenomena. Some insight is gained into the possible roles to be played by tachyons in a particle theory and interesting results are found involving classical Lagrangian and canonical formalisms for lightlike particles.     

The role of pore size and structure on the thermal stability of gold nanoparticles within mesoporous silica

Highly dispersed gold particles (<2 nm) were synthesized within the pores of mesoporous silica with pore sizes ranging from 2.2 to 6.5 nm and different pore structures (2D-hexagonal, 3D-hexagonal, and cubic). The catalysts were reduced in flowing H2 at 200 degrees C and then used for CO oxidation at temperatures ranging from 25 to 400 degrees C. The objective of this study was to investigate the role of pore size and structure in controlling the thermal sintering of Au nanoparticles. Our study shows that sintering of Au particles is dependent on pore size, pore wall thickness (strength of pores), and pore connectivity. A combination of high-resolution TEM/STEM and SEM was used to measure the particle size distribution and to determine whether the Au particles were located within the pores or had migrated to the external silica surface.     

The dark side of disulfide-based dynamic combinatorial chemistry

During the last two decades, disulfide-based dynamic combinatorial chemistry has been extensively used in the field of molecular recognition to deliver artificial receptors for molecules of biological interest. Commonly, the nature of library members and their relative amounts are provided from HPLC-MS analysis of the libraries, allowing the identification of potential binders for a target (bio)molecule. By re-investigating dynamic combinatorial libraries generated from a simple 2,5-dicarboxy-1,4-dithiophenol building block in water, we herein demonstrated that multiple analytical tools were actually necessary in order to comprehensively describe the libraries in terms of size, stereochemistry, affinity, selectivity, and finally to get a true grasp on the different phenomena at work within dynamic combinatorial systems.

We show that multiple analytical tools are necessary in order to describe the different phenomena within disulfide-based dynamic combinatorial libraries in terms of size, stereochemistry, affinity and selectivity.     

Two- and three-body photodissociation of gas phase I(3) (-)

The photodissociation dynamics of I3- from 390 to 290 nm (3.18 to 4.28 eV) have been investigated using fast beam photofragment translational spectroscopy in which the products are detected and analyzed with coincidence imaging. At photon energies < or = 3.87 eV, two-body dissociation that generates I- + I2(A 3Pi1) and vibrationally excited I2- (X 2Sigmau+) + I(2P(3/2)) is observed, while at energies > or = 3.87 eV, I*(2P(1/2)) + I2- (X 2Sigmau+) is the primary two-body dissociation channel. In addition, three-body dissociation yielding I- +2I(2P(3/2)) photofragments is seen throughout the energy range probed; this is the dominant channel at all but the lowest photon energy. Analysis of the three-body dissociation events indicates that this channel results primarily from a synchronous concerted decay mechanism.     

The H method: hydrogen atoms with a fictitious nuclear charge. A versatile theoretical tool for study of atom and group properties as substituents: electronegativity and partition of σ and π contributions

We present a preliminary work for a general method of computing the partition of σ and π electronic effects of a given atom A or substituent R on a given substrate. In this aim, the nuclear charge Z^* of a fictitious hydrogen atom H^* is fitted in order that the A–H^* (or R–H^*) bond be purely covalent, i.e. the Mulliken electron population be one electron on H^*. We obtain this way entities of the same electronegativity as A or R, thus having a comparable σ effect, without any π effect.

The values of Z^* obtained for A–H^* diatomic molecules (A=H–Br) exhibit a good linear correlation with the Allred–Rochow scale of electronegativity, as it could be expected on theoretical grounds. The method, applied to R–H^* molecules, allows a determination of the electronegativity of a variety of polyatomic R substituents, and provides H^*(R) having the same inductive effect as R. These results are discussed by comparison with some previous theoretical and experimental data.

As an example of application, the partition of σ and π contributions of R on the ¹³C chemical shifts in a series of monosubstituted benzenes RC₆H₅ has been computed.