The gas-phase structure of the asymmetric, trans-dinitrogen tetroxide (N 2 O 4), formed by dimeri... more The gas-phase structure of the asymmetric, trans-dinitrogen tetroxide (N 2 O 4), formed by dimerization of nitrogen dioxide (NO 2), from rotational spectroscopy and ab initio quantum chemistry
The effect of oriented external electric fields (OEEF) on chemical reactivity has been studied th... more The effect of oriented external electric fields (OEEF) on chemical reactivity has been studied theoretically and computationally in the last decades. A central goal in this research area is to predict the orientation and the smallest amplitude electric field that renders a barrierless chemical process with the smallest possible strength. Recently, a model to find the optimal electric field has been proposed and described (Bofill JM et al., J. Chem. Theory Comput. 18:935, 2022). We here proof that this model is based on catastrophe and optimum control theories. Based on both theories a technical treatment of the model is given and applied to a two-dimensional generic example that provides insight into its nature and capability. Finally, the model is applied to determine the optimal OEEF for the trans-to-cis isomerization of a [3]cumulene derivative.
We propose a new but simpler explanation of the phases of a Frenkel-Kontorova chain of atoms, and... more We propose a new but simpler explanation of the phases of a Frenkel-Kontorova chain of atoms, and we demonstrate it by examples. Combined with this, we present a criticism of the theory of so-called commensurate and incommensurate states, especially for finite chains. We reject the putative observation of an Aubry-phase transition in a finite chain.
We explain the emergence of zero field steps (ZFS) in a Frenkel-Kontorova (FK) model for a 1D ann... more We explain the emergence of zero field steps (ZFS) in a Frenkel-Kontorova (FK) model for a 1D annular chain being a model for an annular Josephson junction array. We demonstrate such steps for a case with a chain of 10 phase differences. We necessarily need the periodic boundary conditions. We propose a mechanism for the jump from M fluxons to $$M+1$$ M + 1 in the chain. Graphic abstract
Reactive collisions between n-C(3)H(7)Cl molecules and lithium ions both in their ground electron... more Reactive collisions between n-C(3)H(7)Cl molecules and lithium ions both in their ground electronic state have been studied in the 0.05-7.00 eV center of mass energy range using an octopole radio frequency guided-ion beam apparatus developed in our laboratory and recently modified. At low collision energies, dehydrohalogenation reactions leading to Li(C(3)H(6))(+) and Li(HCl)(+) are the main reaction channels, while on increasing energies C(3)H(7)(+) and C(2)H(3)(+) formation become dominant. Cross section energy dependences in arbitrary units for all these reactions have been measured. Also, ab initio electronic structure calculations at the MP2 level have been performed to obtain information about the potential energy surface on which the reactive processes take place. The reactants' entrance channel leads to the formation of a stable [Li-n-C(3)H(7)Cl](+) ion-molecule adduct that, following an intrinsic-reaction-coordinate pathway and surmounting a transition state, isomerizes to [Li-i-C(3)H(7)Cl](+). From this second minimum, dehydrohalogenation reactions for both n-C(3)H(7)Cl and i-C(3)H(7)Cl share a common reaction pathway leading to the same products. All potential barriers explored by reactions always lie below the reactants' energy. The entrance reaction channel [Li-n-C(3)H(7)Cl](+) adduct also leads adiabatically to C(3)H(7)(+) formation which, on increasing collision energy generates C(2)H(3)(+)via a unimolecular decomposition. A qualitative interpretation of the experimental results based on our ab initio calculations is also given.
Inelastic electronically non-adiabatic reactions between Na+ ions and neutral ZnBr2 molecules, bo... more Inelastic electronically non-adiabatic reactions between Na+ ions and neutral ZnBr2 molecules, both in their electronic ground state, have been studied using crossed beams techniques and measuring the decaying emission radiation of the excited species produced. The fluorescent emission corresponding to Na(3 2P) produced by a charge transfer reaction was observed, as well as that corresponding to the decay of Zn(4s 5s 3S), generated by dissociation of the neutral target molecule, to Zn(4s 4p 3P). The phosphorescent decaying emission of Zn*(4s 4p 3P) to the zinc ground state was also observed. For each emission process, the cross section energy dependences have been measured in the 0.10–3.50 keV energy range in the laboratory system. The ground electronic state of the (NaZnBr2)+ collision system has been characterized by ab initio chemical structure calculations at the second order Möller-Plesset perturbation level of theory using pseudo-potentials. By performing restricted open shell...
We study a Frenkel-Kontorova model of a finite chain with free-end boundary conditions. The model... more We study a Frenkel-Kontorova model of a finite chain with free-end boundary conditions. The model has two competing potentials. Newton trajectories are an ideal tool to understand the circumstances under a driving of a Frenkel-Kontorova chain by external forces. To reach the insights we calculate some stationary structures for a chain with 23 particles. We search the lowest energy saddle points for a complete minimum energy path of the chain for a movement over the full period of the on-site potential, a sliding. If an additional tilting is set, then one is interested in barrier breakdown points on the potential energy surface for a critical tilting force named the static frictional force. In symmetric cases, such barrier breakdown points are often valley-ridge inflection points of the potential energy surface. We explain the theory and demonstrate it with an example. We propose a model for a DC drive, as well as an AC drive, of the chain using special directional vectors of the external force.
We present a computational study of a reduced potential energy surface (PES) to describe enantiom... more We present a computational study of a reduced potential energy surface (PES) to describe enantiomerization and internal rotation in three triptycyln-helicene molecules, centering the discussion on the issue of a proper reaction coordinate choice. To reflect the full symmetry of both strongly coupled enantiomerization and rotation processes, two non-fixed combinations of dihedral angles must be used, implying serious computational problems that required the development of a complex general algorithm. The characteristic points on each PES are analyzed, the intrinsic reaction coordinates calculated, and finally projected on the reduced PES. Unlike what was previously found for triptycyl-3-helicene, the surfaces for triptycyl-4-helicene and triptycyl-5-helicene contain valleyridge-inflection (VRI) points. The reaction paths on the reduced surfaces are analyzed to understand the dynamical behaviour of these molecules and to evaluate the possibility of a molecule of this family exhibiting a Brownian ratchet behaviour.
Pages 2509-2521. We thank an anonymous reader of our manuscript for bringing the following import... more Pages 2509-2521. We thank an anonymous reader of our manuscript for bringing the following important reference to our attention. Bendikov et al. reported that polyacenes longer than pentacene possess open-shell singlet diradical ground states. The possibility of an openshell singlet state was not considered in our investigation.
This article has been published as a chapter in "Chemical Reactivity Theory: A Density Functional... more This article has been published as a chapter in "Chemical Reactivity Theory: A Density Functional View", ed. P. K. Chattaraj (CRC Press, New York, 2009), ch. 8, p. 105. In it, an overview of the relationship between time-dependent DFT and quantum hydrodynamics is presented, showing the role that Bohmian mechanics can play within the ab-initio methodology as both a numerical and an interpretative tool.
We discuss the twist map, with a special interest in its use for the finite Frenkel–Kontorova mod... more We discuss the twist map, with a special interest in its use for the finite Frenkel–Kontorova model. We explain the meaning of the tensile force in some proposed models. We demonstrate that the application of the twist map for the finite FK model is not correct, because the procedure ignores the necessary boundary conditions.
We explain the propagating austenite–martensite phase boundary by a Frenkel–Kontorova model for a... more We explain the propagating austenite–martensite phase boundary by a Frenkel–Kontorova model for a chain of meshes along a ledge of the phase transitions. We demonstrate such steps for example chains of 16 and 47 meshes. We can represent a Langevin solution which describes possible cases of a consecutive excitation of a higher phase under a low external force. Graphic abstract
The equilibration of the double proton transfer in porphine is demonstrated using a model system ... more The equilibration of the double proton transfer in porphine is demonstrated using a model system Hamiltonian. This highly coherent process could be witnessed experimentally using state-of-the-art femtosecond spectroscopy.
There is a renewed interest in the derivation of statistical mechanics from the dynamics of close... more There is a renewed interest in the derivation of statistical mechanics from the dynamics of closed quantum systems. A central part of this program is to understand how far-from-equilibrium closed quantum system can behave as if relaxing to a stable equilibrium. Equilibration dynamics has been traditionally studied with a focus on the so-called quenches of large-scale many-body systems. Alternatively, we consider here the equilibration of a molecular model system describing the double proton transfer reaction in porphine. Using numerical simulations, we show that equilibration in this context indeed takes place and does so very rapidly ($\sim \!\! 200$fs) for initial states induced by pump-dump laser pulse control with energies well above the synchronous tunneling barrier.
Newton trajectories are used to calculate low energy pathways for a series of Frenkel-Kontorova m... more Newton trajectories are used to calculate low energy pathways for a series of Frenkel-Kontorova models with 6 and up to 69 particles thus up to a medium chain, and an expedition to 101 particles. The model is a finite chain with free-end boundary conditions. It has two competing potentials and an additional, external force. We optimize stationary structures and calculate the low energy paths between global minimums for a movement of the chain over its on-site potential, if an external tilting by a pushand/or pull direction is applied. We propose to understand a low energy path for a possibility of a superlubricity of the chain. We compare different misfit parameters. The result is that the minimums differ only little, however, the critical length of the chain, Ncr, depends on the misfit parameter. Ncr describes the end of a 'good' calculability of the Newton trajectory which follows the low energy pathway of the chain through the potential energy surface, for a movement of the chain along the axis. We discuss reasons for the boundary of an Ncr. However, we assume that the low energy paths exist beyond their calculability by NTs.
Dehydrohalogenation and dehydration reactions of gasphase i-C 3 H 7 Br and i-C 3 H 7 OH molecules... more Dehydrohalogenation and dehydration reactions of gasphase i-C 3 H 7 Br and i-C 3 H 7 OH molecules induced by collision with Na + , all participants being in their electronic ground state, were studied experimentally in our laboratory using a radiofrequency-guided ion beam apparatus and covering the 0.10−10.00 eV center of mass (CM) energy range. In Na + + i-C 3 H 7 Br collisions the formation of [C 3 H 6 −Na] + and [HBr−Na] + by dehydrohalogenation was observed and quantified, as well as that of the ion−molecule adduct [Na−i-C 3 H 7 Br] + together with its decomposition products C 3 H 7 + and NaBr. In Na + + i-C 3 H 7 OH collisions the dehydration product [H 2 O−Na] + was also found, while [C 3 H 6 −Na] + was hardly detected. Moreover, the [Na−i-C 3 H 7 OH] + adduct formation as well as its decomposition into C 3 H 7 + and NaOH were also quantified. For all these processes, absolute reaction cross sections were measured as a function of the CM collision energy. From measured excitation functions, rate constants for the formation of [C 3 H 6 −Na] + , [HBr−Na] + , and [H 2 O−Na] + at 303 K were obtained. Complementing the experiments, exhaustive ab initio structure calculations at the MP2 level of theory were performed, giving information on the most relevant features of the potential energy surfaces (PESs) where the dehydrohalogenation, dehydration, and decomposition reactions take place adiabatically for both collision systems. On these PESs different stationary points associated with potential energy minima and transition state barriers were characterized, and their connectivity was ensured using the intrinsic-reactioncoordinate method. The main topology features of the ab initio calculated PESs allowed a qualitative interpretation of the experimental data also exposing the role of the sodium ion as a catalyst in elimination reactions. 50 propyl chloride and isopropyl bromide induced by lithium ion 51 collisions at low energy using molecular beam techniques and 52 at a few defined collision energies, measuring the corresponding 53 branching ratios for the different reaction channels. In our 54 previous studies on ion−molecule dehydrohalogenation or 55 dehydration reactions, 6,13−17 we measured the corresponding 56 excitation functions for different reaction channels including 57 some not previously observed. 9−12 These studies were 58 complemented by ab initio calculations of the corresponding 59 ground singlet state potential energy surfaces (PES) on which 60 the reactive processes take place adiabatically at low collision 61 energies. 62 In the present work we report on the reactive processes 63 taking place in collisions between Na + and i-C 3 H 7 Br or i-64 C 3 H 7 OH molecules, all reactants being in their singlet ground 65 state. According to previous experiments, we expected to
Collisions between potassium ions and neutral i-C3H7Br and i-C3H7OH, all in their electronic grou... more Collisions between potassium ions and neutral i-C3H7Br and i-C3H7OH, all in their electronic ground state, have been studied in the 0.10–10.00 eV center of mass (CM) collision energy range, using the radiofrequency-guided ion beam technique. In K+ + i-C3H7Br collisions KHBr+ formation was observed and quantified, while the analogous KH2O+ formation in K+ + i-C3H7OH was hardly detected. Moreover, formation of the ion-molecule adducts and their decomposition leading to C3H7+ and either KBr or KOH, respectively, have been observed. For all these processes, absolute cross-sections were measured as a function of the CM collision energy. Ab initio structure calculations at the MP2 level have given information about the potential energy surfaces (PESs) involved. In these, different stationary points have been characterized using the reaction coordinate method, their connectivity being ensured by using the intrinsic-reaction-coordinate method. From the measured excitation function for KHBr+...
The gas-phase structure of the asymmetric, trans-dinitrogen tetroxide (N 2 O 4), formed by dimeri... more The gas-phase structure of the asymmetric, trans-dinitrogen tetroxide (N 2 O 4), formed by dimerization of nitrogen dioxide (NO 2), from rotational spectroscopy and ab initio quantum chemistry
The effect of oriented external electric fields (OEEF) on chemical reactivity has been studied th... more The effect of oriented external electric fields (OEEF) on chemical reactivity has been studied theoretically and computationally in the last decades. A central goal in this research area is to predict the orientation and the smallest amplitude electric field that renders a barrierless chemical process with the smallest possible strength. Recently, a model to find the optimal electric field has been proposed and described (Bofill JM et al., J. Chem. Theory Comput. 18:935, 2022). We here proof that this model is based on catastrophe and optimum control theories. Based on both theories a technical treatment of the model is given and applied to a two-dimensional generic example that provides insight into its nature and capability. Finally, the model is applied to determine the optimal OEEF for the trans-to-cis isomerization of a [3]cumulene derivative.
We propose a new but simpler explanation of the phases of a Frenkel-Kontorova chain of atoms, and... more We propose a new but simpler explanation of the phases of a Frenkel-Kontorova chain of atoms, and we demonstrate it by examples. Combined with this, we present a criticism of the theory of so-called commensurate and incommensurate states, especially for finite chains. We reject the putative observation of an Aubry-phase transition in a finite chain.
We explain the emergence of zero field steps (ZFS) in a Frenkel-Kontorova (FK) model for a 1D ann... more We explain the emergence of zero field steps (ZFS) in a Frenkel-Kontorova (FK) model for a 1D annular chain being a model for an annular Josephson junction array. We demonstrate such steps for a case with a chain of 10 phase differences. We necessarily need the periodic boundary conditions. We propose a mechanism for the jump from M fluxons to $$M+1$$ M + 1 in the chain. Graphic abstract
Reactive collisions between n-C(3)H(7)Cl molecules and lithium ions both in their ground electron... more Reactive collisions between n-C(3)H(7)Cl molecules and lithium ions both in their ground electronic state have been studied in the 0.05-7.00 eV center of mass energy range using an octopole radio frequency guided-ion beam apparatus developed in our laboratory and recently modified. At low collision energies, dehydrohalogenation reactions leading to Li(C(3)H(6))(+) and Li(HCl)(+) are the main reaction channels, while on increasing energies C(3)H(7)(+) and C(2)H(3)(+) formation become dominant. Cross section energy dependences in arbitrary units for all these reactions have been measured. Also, ab initio electronic structure calculations at the MP2 level have been performed to obtain information about the potential energy surface on which the reactive processes take place. The reactants' entrance channel leads to the formation of a stable [Li-n-C(3)H(7)Cl](+) ion-molecule adduct that, following an intrinsic-reaction-coordinate pathway and surmounting a transition state, isomerizes to [Li-i-C(3)H(7)Cl](+). From this second minimum, dehydrohalogenation reactions for both n-C(3)H(7)Cl and i-C(3)H(7)Cl share a common reaction pathway leading to the same products. All potential barriers explored by reactions always lie below the reactants' energy. The entrance reaction channel [Li-n-C(3)H(7)Cl](+) adduct also leads adiabatically to C(3)H(7)(+) formation which, on increasing collision energy generates C(2)H(3)(+)via a unimolecular decomposition. A qualitative interpretation of the experimental results based on our ab initio calculations is also given.
Inelastic electronically non-adiabatic reactions between Na+ ions and neutral ZnBr2 molecules, bo... more Inelastic electronically non-adiabatic reactions between Na+ ions and neutral ZnBr2 molecules, both in their electronic ground state, have been studied using crossed beams techniques and measuring the decaying emission radiation of the excited species produced. The fluorescent emission corresponding to Na(3 2P) produced by a charge transfer reaction was observed, as well as that corresponding to the decay of Zn(4s 5s 3S), generated by dissociation of the neutral target molecule, to Zn(4s 4p 3P). The phosphorescent decaying emission of Zn*(4s 4p 3P) to the zinc ground state was also observed. For each emission process, the cross section energy dependences have been measured in the 0.10–3.50 keV energy range in the laboratory system. The ground electronic state of the (NaZnBr2)+ collision system has been characterized by ab initio chemical structure calculations at the second order Möller-Plesset perturbation level of theory using pseudo-potentials. By performing restricted open shell...
We study a Frenkel-Kontorova model of a finite chain with free-end boundary conditions. The model... more We study a Frenkel-Kontorova model of a finite chain with free-end boundary conditions. The model has two competing potentials. Newton trajectories are an ideal tool to understand the circumstances under a driving of a Frenkel-Kontorova chain by external forces. To reach the insights we calculate some stationary structures for a chain with 23 particles. We search the lowest energy saddle points for a complete minimum energy path of the chain for a movement over the full period of the on-site potential, a sliding. If an additional tilting is set, then one is interested in barrier breakdown points on the potential energy surface for a critical tilting force named the static frictional force. In symmetric cases, such barrier breakdown points are often valley-ridge inflection points of the potential energy surface. We explain the theory and demonstrate it with an example. We propose a model for a DC drive, as well as an AC drive, of the chain using special directional vectors of the external force.
We present a computational study of a reduced potential energy surface (PES) to describe enantiom... more We present a computational study of a reduced potential energy surface (PES) to describe enantiomerization and internal rotation in three triptycyln-helicene molecules, centering the discussion on the issue of a proper reaction coordinate choice. To reflect the full symmetry of both strongly coupled enantiomerization and rotation processes, two non-fixed combinations of dihedral angles must be used, implying serious computational problems that required the development of a complex general algorithm. The characteristic points on each PES are analyzed, the intrinsic reaction coordinates calculated, and finally projected on the reduced PES. Unlike what was previously found for triptycyl-3-helicene, the surfaces for triptycyl-4-helicene and triptycyl-5-helicene contain valleyridge-inflection (VRI) points. The reaction paths on the reduced surfaces are analyzed to understand the dynamical behaviour of these molecules and to evaluate the possibility of a molecule of this family exhibiting a Brownian ratchet behaviour.
Pages 2509-2521. We thank an anonymous reader of our manuscript for bringing the following import... more Pages 2509-2521. We thank an anonymous reader of our manuscript for bringing the following important reference to our attention. Bendikov et al. reported that polyacenes longer than pentacene possess open-shell singlet diradical ground states. The possibility of an openshell singlet state was not considered in our investigation.
This article has been published as a chapter in "Chemical Reactivity Theory: A Density Functional... more This article has been published as a chapter in "Chemical Reactivity Theory: A Density Functional View", ed. P. K. Chattaraj (CRC Press, New York, 2009), ch. 8, p. 105. In it, an overview of the relationship between time-dependent DFT and quantum hydrodynamics is presented, showing the role that Bohmian mechanics can play within the ab-initio methodology as both a numerical and an interpretative tool.
We discuss the twist map, with a special interest in its use for the finite Frenkel–Kontorova mod... more We discuss the twist map, with a special interest in its use for the finite Frenkel–Kontorova model. We explain the meaning of the tensile force in some proposed models. We demonstrate that the application of the twist map for the finite FK model is not correct, because the procedure ignores the necessary boundary conditions.
We explain the propagating austenite–martensite phase boundary by a Frenkel–Kontorova model for a... more We explain the propagating austenite–martensite phase boundary by a Frenkel–Kontorova model for a chain of meshes along a ledge of the phase transitions. We demonstrate such steps for example chains of 16 and 47 meshes. We can represent a Langevin solution which describes possible cases of a consecutive excitation of a higher phase under a low external force. Graphic abstract
The equilibration of the double proton transfer in porphine is demonstrated using a model system ... more The equilibration of the double proton transfer in porphine is demonstrated using a model system Hamiltonian. This highly coherent process could be witnessed experimentally using state-of-the-art femtosecond spectroscopy.
There is a renewed interest in the derivation of statistical mechanics from the dynamics of close... more There is a renewed interest in the derivation of statistical mechanics from the dynamics of closed quantum systems. A central part of this program is to understand how far-from-equilibrium closed quantum system can behave as if relaxing to a stable equilibrium. Equilibration dynamics has been traditionally studied with a focus on the so-called quenches of large-scale many-body systems. Alternatively, we consider here the equilibration of a molecular model system describing the double proton transfer reaction in porphine. Using numerical simulations, we show that equilibration in this context indeed takes place and does so very rapidly ($\sim \!\! 200$fs) for initial states induced by pump-dump laser pulse control with energies well above the synchronous tunneling barrier.
Newton trajectories are used to calculate low energy pathways for a series of Frenkel-Kontorova m... more Newton trajectories are used to calculate low energy pathways for a series of Frenkel-Kontorova models with 6 and up to 69 particles thus up to a medium chain, and an expedition to 101 particles. The model is a finite chain with free-end boundary conditions. It has two competing potentials and an additional, external force. We optimize stationary structures and calculate the low energy paths between global minimums for a movement of the chain over its on-site potential, if an external tilting by a pushand/or pull direction is applied. We propose to understand a low energy path for a possibility of a superlubricity of the chain. We compare different misfit parameters. The result is that the minimums differ only little, however, the critical length of the chain, Ncr, depends on the misfit parameter. Ncr describes the end of a 'good' calculability of the Newton trajectory which follows the low energy pathway of the chain through the potential energy surface, for a movement of the chain along the axis. We discuss reasons for the boundary of an Ncr. However, we assume that the low energy paths exist beyond their calculability by NTs.
Dehydrohalogenation and dehydration reactions of gasphase i-C 3 H 7 Br and i-C 3 H 7 OH molecules... more Dehydrohalogenation and dehydration reactions of gasphase i-C 3 H 7 Br and i-C 3 H 7 OH molecules induced by collision with Na + , all participants being in their electronic ground state, were studied experimentally in our laboratory using a radiofrequency-guided ion beam apparatus and covering the 0.10−10.00 eV center of mass (CM) energy range. In Na + + i-C 3 H 7 Br collisions the formation of [C 3 H 6 −Na] + and [HBr−Na] + by dehydrohalogenation was observed and quantified, as well as that of the ion−molecule adduct [Na−i-C 3 H 7 Br] + together with its decomposition products C 3 H 7 + and NaBr. In Na + + i-C 3 H 7 OH collisions the dehydration product [H 2 O−Na] + was also found, while [C 3 H 6 −Na] + was hardly detected. Moreover, the [Na−i-C 3 H 7 OH] + adduct formation as well as its decomposition into C 3 H 7 + and NaOH were also quantified. For all these processes, absolute reaction cross sections were measured as a function of the CM collision energy. From measured excitation functions, rate constants for the formation of [C 3 H 6 −Na] + , [HBr−Na] + , and [H 2 O−Na] + at 303 K were obtained. Complementing the experiments, exhaustive ab initio structure calculations at the MP2 level of theory were performed, giving information on the most relevant features of the potential energy surfaces (PESs) where the dehydrohalogenation, dehydration, and decomposition reactions take place adiabatically for both collision systems. On these PESs different stationary points associated with potential energy minima and transition state barriers were characterized, and their connectivity was ensured using the intrinsic-reactioncoordinate method. The main topology features of the ab initio calculated PESs allowed a qualitative interpretation of the experimental data also exposing the role of the sodium ion as a catalyst in elimination reactions. 50 propyl chloride and isopropyl bromide induced by lithium ion 51 collisions at low energy using molecular beam techniques and 52 at a few defined collision energies, measuring the corresponding 53 branching ratios for the different reaction channels. In our 54 previous studies on ion−molecule dehydrohalogenation or 55 dehydration reactions, 6,13−17 we measured the corresponding 56 excitation functions for different reaction channels including 57 some not previously observed. 9−12 These studies were 58 complemented by ab initio calculations of the corresponding 59 ground singlet state potential energy surfaces (PES) on which 60 the reactive processes take place adiabatically at low collision 61 energies. 62 In the present work we report on the reactive processes 63 taking place in collisions between Na + and i-C 3 H 7 Br or i-64 C 3 H 7 OH molecules, all reactants being in their singlet ground 65 state. According to previous experiments, we expected to
Collisions between potassium ions and neutral i-C3H7Br and i-C3H7OH, all in their electronic grou... more Collisions between potassium ions and neutral i-C3H7Br and i-C3H7OH, all in their electronic ground state, have been studied in the 0.10–10.00 eV center of mass (CM) collision energy range, using the radiofrequency-guided ion beam technique. In K+ + i-C3H7Br collisions KHBr+ formation was observed and quantified, while the analogous KH2O+ formation in K+ + i-C3H7OH was hardly detected. Moreover, formation of the ion-molecule adducts and their decomposition leading to C3H7+ and either KBr or KOH, respectively, have been observed. For all these processes, absolute cross-sections were measured as a function of the CM collision energy. Ab initio structure calculations at the MP2 level have given information about the potential energy surfaces (PESs) involved. In these, different stationary points have been characterized using the reaction coordinate method, their connectivity being ensured by using the intrinsic-reaction-coordinate method. From the measured excitation function for KHBr+...
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