The potential of a two-dimensional (2D) molybdenum disulfide (MoS2) lateral heterostructure in sensing small gas molecules is being assessed on the basis of quantum mechanical calculations. This heterostructure combines two phases of MoS2, namely, a metallic ribbon embedded within the semiconducting MoS2 phase. In this work the influence on the electronic structure of this 2D material due to the adsorption of gas molecules is investigated. Specifically, the adsorption of NO, NO2, O2, CO, and CO2 on the MoS2 heterostructure is studied. Overall, gas-specific peaks in the electronic features of the 2D material could be clearly revealed, while differences were also found for a gas adsorption close to the interfaces of the material. The “poisonous” nitrogen oxide molecules showed a stronger adsorption on the material but could very well be distinguished over the “healthy” molecular oxygen gas. The complexity of the heterostructure provides more rich gas adsorption characteristics over the single-phase material and is thereby expected to show an enhanced sensitivity due to the increased statistics and the wider window of gate voltages that can be applied. This work provides a proof of principles on the high relevance of the 2D MoS2 heterostructure in view of response materials in gas detectors.

AbstractsA comprehensive review of the attempts to rephrase molecular quantum mechanics in terms of the particle density operator and the current density or phase density operator is given. All pertinent investigations which have come to our attention suffer from severe mathematical inconsistencies and are not adequate to the few-body problem of quantum chemistry. The origin of the failure of these attempts is investigated and it is shown that a realization of a local quantum field theory of molecular matter in terms of observables would presuppose the solution of many highly nontrivial mathematical problems.Dans une revue dttaillte de la IittCrature nous exposons les tentatives de reformuler la mtcanique quantique molCculaire directement ? i I'aide des optrateurs de densitt de particules, de courant ou de phase. Tous les travaux consider& comportent dimportantes inconsistences mathkmatiques et ne sont pas adaptables au problkme pluricorps de la chimie quantique. A la suite d'une Ctude sur les raisons de cet Cchec on montre que la rtalisation d'une thCorie de champs quantique local en termes d'observables implique la rtsolution de nombreux problkmes mathkmatiques qui w i t loin5 d'ctre triviauu.

AbstractsA mathematically rigorous reformulation of molecular quantum mechanics in terms of the particle density operator and a canonically conjugated phase field is given. Using a momentum cutoff, it is shown that the usual molecular Hamiltonian can be expressed in terms of the particle density operator and a rigorously defined phase operator. It is shown that this Hamiltonian converges strongly to the cutoff-free Hamiltonian. In spite of the fact that this Hamiltonian is of second order in the phase operators, all hitherto published expressions are not correct. Unfortunately, the correct formulation destroys the intuitive appeal of using the particle density operator as a coordinate for the many-body problems of quantum chemistry. Unless somebody provides an essential new and clever idea, we propose to resist the fascination of a local quantum field theory of molecular matter in terms of the particle density operator.On utilise I'opCrateur de densit6 de particules et son conjuguC, l'operateur de densit6 de phase, comme variables dynamiques fondamentales pour reformuler la mdcanique quantique molCculaire en toute rigueur mathtmatique. Par limitation d'impulsion l'hahituel Hamiltonien moliculaire peut Ctre exprim6 exactement B l'aide d'un opCrateur de densit6 de charge et d'un opkrateur de phase dtfinis rigoureusement. On dCmontre que cet opdrateur converge dans la topologie forte vers l'Hamiltonien sans limitation d'impulsion. Bien que 1'Hamiltonien ne contienne l'op6rateur de phase qu'en second ordre, toutes les formulations antCrieures se revitlent n'Ctre pas correctes. Malheureusement, la formulation exacte du problbme enlkve a une telle entreprise une grande partie de son intCrCt. A notre avis on ne peut espCrer que la reformulation de la mCcanique quantique molCculaire B l'aide de l'opkrateur de densitC de particules puisse Ctre d'une utilitd quelquonque, avant que n'apparaissent des idCes substantiellement neuves et pourvues d'intelligence.