Erratum: Highly Adiabatic Time-Optimal Quantum Driving at Low Energy Cost [Phys. Rev. Lett. 129, 180402 (2022)].

This corrects the article DOI: 10.1103/PhysRevLett.129.180402.

The reactivity of cyclopropyl cyanide in titan's atmosphere: a possible pre-biotic mechanism.

Cyclopropyl cyanide and other simple nitriles detected in Titan's atmosphere could be precursors leading to the formation of organic macromolecules in the atmosphere of Saturn's largest satellite. Proposing a thermodynamically possible mechanism that explains their formation and supports experimental results represents a difficult challenge. Experiments done in the Atomic and Molecular Physics Laboratory at the University of Trento (AMPL) have studied the ion-molecule reaction between cyclopropyl cyanide and its protonated form, with reaction products being characterized by mass spectrometry. In addition to the expected ion-molecule adduct stabilized by non-covalent long-range interactions, in this work we prove that another distinct species having the same mass to charge ratio (m/z) of 135 is also produced. Moreover, from a previous study of the neutral cyclopropyl cyanide potential energy surface (PES) which shows a partial biradical character it has been possible to characterize the formation through the bimolecular reaction of a new covalent cyclic organic molecule. Calculations have been carried out at the ab initio Møller-Plesset (MP2) level of theory, ensuring the connectivity of the stationary points by using the intrinsic reaction coordinate (IRC) procedure. In order to characterize the reaction transition state, multireference calculations were done using a complete active space involving six electrons and six molecular orbitals [CAS (6 e-, 6 m.o.)]. This study opens the possibility of exploring the formation of new organic molecules by gaseous phase ion-molecule interaction schemes, with such molecules having relevance in interstellar space and in astrobiology (and may be involved in prebiotic molecular evolution).

The role of Li+ ions in the gas phase dehydrohalogenation and dehydration reactions of i-C3H7Br and i-C3H7OH molecules studied by radiofrequency-guided ion beam techniques and ab initio methods.

Gas phase reactive collisions between lithium ions and i-C3H7X (X = Br, OH) molecules have been studied under single collision conditions in the center of mass (CM) 0.01-10.00 eV energy range using a radiofrequency-guided ion beam apparatus. Mass spectrometry analysis of the products did show the presence of [C3H6-Li]+, [HX-Li]+, C3H7+, and C2H3+ as well as of the [Li-i-C3H7Br]+ adduct while [Li-i-C3H7OH]+ was hardly detected. For all these reactive processes, the corresponding cross sections have been measured in absolute units as a function of the CM collision energy. Quantum chemistry ab initio calculations done at the second order Möller Plesset level have provided relevant information on the topology of the potential energy surfaces (PESs) where a reaction takes place allowing the characterization of the stationary points on the respective PESs along their reaction pathways. The connectivity of the different stationary points localized on the PESs was ensured by using the intrinsic reaction coordinate (IRC) method, confirming the adiabatic character of the reactions. The main topology features of the reactive PESs, in the absence of dynamical calculations, were used to interpret at the qualitative level the behavior of the experimental excitations functions, evidencing the role played by the potential energy barriers on the experimental dynamics of the reactions. Reaction rate constants at 303.2 K for different reactions have been calculated from measured excitation functions.

Dehydrohalogenation and Dehydration Reactions of i-C3H7Br and i-C3H7OH by Sodium Ions Studied by Guided Ion Beam Techniques and Quantum Chemical Methods.

Dehydrohalogenation and dehydration reactions of gas-phase i-C3H7Br and i-C3H7OH 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-C3H7Br collisions the formation of [C3H6-Na](+) and [HBr-Na](+) by dehydrohalogenation was observed and quantified, as well as that of the ion-molecule adduct [Na-i-C3H7Br](+) together with its decomposition products C3H7(+) and NaBr. In Na(+) + i-C3H7OH collisions the dehydration product [H2O-Na](+) was also found, while [C3H6-Na](+) was hardly detected. Moreover, the [Na-i-C3H7OH](+) adduct formation as well as its decomposition into C3H7(+) 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 [C3H6-Na](+), [HBr-Na](+), and [H2O-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-reaction-coordinate 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.

[Obtaining a formula that improves maximum oxygen consumption estimation in cycle ergometer exercise tests]. / Obtención de una fórmula que mejora la estimación del consumo máximo de oxígeno en las pruebas de esfuerzo con bicicleta ergométrica.

OBJECTIVES: To evaluate if the estimation of the maximal oxygen consumption (MO2C) in METs (metabolic equivalents) by means of the table proposed in the guidelines of the Spanish Society of Cardiology is a sufficiently reliable method when applied to the bicycle exercise test. MATERIAL AND METHODS: The MO2C in METs was obtained by gas-exchange analysis on bicycle ergometer tests in 97 healthy subjects (group i). It was compared with the estimate of METs using the table in which only watts and patient's weight were included. A better-adjusted formula was validated in 289 subjects with normal exercise myocardial perfusion gated-SPECT (group ii) using the introduction of clinical and ergometric variables. RESULTS: In group i individuals a good correlation between METs estimated with the table and those obtained through gas-exchange analysis (CCI: 0.93) was observed. However, the best adjusted formula to estimate METs in group ii subjects included watts, body mass index (BMI), age and gender (METS=11.820-0.054×age-0.189×BMI+1.031×gender+0.020×watts) (women: 0, men: 1). This formula allowed the reclassification of 46.9% of group ii subjects into the category <5METs versus the estimation by table. CONCLUSIONS: Estimating the METs with the conventional table is reliable. However, the best adjustment in subjects with normal bicycle exercise SPECT was obtained when, in addition to watts and BMI, age and gender were also considered.

Experimental and ab initio studies of the reactive processes in gas phase i-C3H7Br and i-C3H7OH collisions with potassium ions.

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(+) formation the corresponding thermal rate constant at 303 K has been calculated. The topology of the calculated PESs allows an interpretation of the main features of the reaction dynamics of both systems, and in particular evidence the important role played by the potential energy wells in controlling the reactivity for the different reaction channels.

Crossed molecular beams study of inelastic non-adiabatic processes in gas phase collisions between sodium ions and ZnBr2 molecules in the 0.10-3.50 keV energy range.

Inelastic electronically non-adiabatic reactions between Na(+) ions and neutral ZnBr(2) 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 (2)P) produced by a charge transfer reaction was observed, as well as that corresponding to the decay of Zn(4s 5s (3)S), generated by dissociation of the neutral target molecule, to Zn(4s 4p (3)P). The phosphorescent decaying emission of Zn*(4s 4p (3)P) 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 (NaZnBr(2))(+) 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 Hartree-Fock calculations for C(2v) geometries, four singlet and four triplet potential energy surfaces of the system have been calculated and used to interpret qualitatively the observed reactions. A simple two-state dynamical model is presented that allows an estimation of the maximum values for measured cross sections at high collision energies to be made.

Cross-section energy dependence of the [C6H6-M]+ adduct formation between benzene molecules and alkali ions (M = Li, Na, K).

The association reactions of benzene molecules with alkali ions M(+) (Li(+), Na(+) and K(+)) under single collision conditions have been studied using a radiofrequency-guided-ion-beam apparatus and mass spectrometry characterization of the different adducts. Cross-section energy dependences for [M-C(6)H(6)](+) adduct formation have been measured at collision energies up to 1.20 eV in the center of mass frame. All excitation functions decrease when collision energy increases, showing the expected behaviour for barrierless reactions. From ab initio chemical structure calculations at the MP2(full) level, the formation of the adducts makes evident the alkali ion-benzene non-covalent chemical bond. The cross-section energy dependence and the role of radiative cooling rates and unimolecular decomposition on the stabilization of the energized collision complex are also discussed.

Guided-ion-beam and ab initio study of the Li+, K+, and Rb+ association reactions with gas-phase butanone and cyclohexanone in their ground electronic states.

The association reactions between Li(+), K(+), and Rb(+) (M) and butanone and cyclohexanone molecules under single collision conditions have been studied using a radiofrequency-guided ion-beam apparatus, characterizing the adducts by mass spectrometry. The excitation function for the [M-(molecule)](+) adducts (in arbitrary units) has been obtained at low collision energies in the 0.10 eV up to a few eV range in the center of mass frame. The measured relative cross sections decrease when collision energy increases, showing the expected energy dependence for adduct formation. The energetics and structure of the different adducts have been calculated ab initio at the MP2(full) level, showing that the M(+)-molecule interaction takes place through the carbonyl oxygen atom, as an example of a nontypical covalent chemical bond. The cross-section energy dependence and the role of radiative cooling rates allowing the stabilization of the collision complexes are also discussed.

An experimental guided-ion-beam and ab initio study of the ion-molecule gas-phase reactions between Li+ ions and iso-C3H7Cl in their ground electronic state.

Reactive collisions between Li(+) ions and i-C(3)H(7)Cl molecules have been studied in the 0.20-12.00 eV center-of-mass energy range using an octopole radio frequency guided-ion beam apparatus recently developed in our laboratory. At low collision energies, dehydrohalogenation reactions giving rise to Li(C(3)H(6))(+) and Li(HCl)(+) are the main reaction channels, while at higher ones C(3)H(7)(+) and C(2)H(3)(+) become dominant, all their reactive cross sections having been measured as a function of the collision energy. To obtain information about the potential energy surfaces (PESs) on which the reactive processes take place, ab initio calculations at the MP2 level have been performed. For dehydrohalogenations, the reactive ground singlet PES shows ion-molecule adduct formation in both the reactant and product sides of the surface. Following the minimum energy path connecting both minima, an unstable intermediate and the corresponding barriers, both lying below the reactant's energy, have been characterized. The entrance channel ion-molecule adduct is also involved in the formation of C(3)H(7)(+), which then generates C(2)H(3)(+) via an CH(4) unimolecular elimination. A qualitative interpretation of the experimental results based on ab initio calculations is also included.

Inelastic electronic excitation and electron transfer processes in collisions between Mg(31S0) atoms and K+(1S0) ions studied by crossed beams in the 0.10-3.80-keV energy range.

Inelastic and charge-transfer excitation processes in collisions between ground-state neutral Mg atoms and K+ ions have been studied by means of a crossed molecular-beam technique. Decay fluorescent emissions from Mg(3 1P1),Mg(4 3S1), and Mg(3s(1)3d(1), 3(3)D3,2,1) as well as the phosphorescent emission due to Mg(3 3P1) have been observed from excited Mg atoms and the charge-transfer emission decays from K(4 2P 3/2,1/2), K(5 2P 3/2, 1/2), K(6 2S 1/2), and K(4 2D 5/2, 3/2) for excited K atoms. The corresponding absolute cross-sections values versus collision energy functions were determined in the 0.10-3.80 keV laboratory energy range. In order to interpret the experimental results, accurate ab initio full configuration-interaction calculations using pseudopotentials have been performed for the (Mg-K)+ system, giving a manifold of adiabatic singlet and triplet potential-energy curves correlating with the different collision channels, which allow a qualitative interpretation of the emission excitation functions measured for the different processes studied. A comparative study with other Mg-alkali ion systems previously studied is also included.

Electronic excitation and charge transfer processes in collisions between Mg(3(1)S0) atoms and Rb+(1S0) ions in the 0.07-4.00 keV energy range.

Inelastic collision processes between neutral Mg atoms and Rb(+) ions, both in their ground states, have been studied by means of a crossed molecular beam technique measuring the decay fluorescence of the excited species formed. Emissions corresponding to Mg(3 (1)P(1)), Mg(3 (3)D(3,2,1)), and Mg(4 (3)S(1)), formed by direct target excitation, Rb(5 (2)P(3/2,1/2)), Rb(6 (2)P(3/2,1/2)) produced by electron capture and also the phosphorescent emission due to decay of Mg(3 (3)P(1)), have been detected and the corresponding absolute cross-section values measured both as total values and resolved into their J states. No polarization measurements could be made. Ab initio calculations using pseudopotentials have been performed and from these a manifold of adiabatic energy curves correlating with the different entry and exit channels have been obtained, allowing to propose a qualitative interpretation of the results, such as the shape of the cross section vs energy for different transitions and the oscillating nature of the branching ratios due to interference effects.

Ab initio calculations on the mechanism of the oxidation of the hydroxymethyl radical by molecular oxygen in the gas phase: a significant reaction for environmental science.

The mechanism of the gas-phase reaction of *CH2OH+O2 to form CH2O+HO2* was studied theoretically by means of high-level quantum-chemical electronic structure methods (CASSCF and CCSD(T)). The calculations indicate that the oxidation of *CH2OH by O2 is a two-step process that goes through the peroxy radical intermediate *OOCH2OH (1), formed by the barrier-free radical addition of *CH2OH to O2. The concerted elimination of HO2* from 1 is predicted to occur via a five-membered ringlike transition structure of Cs symmetry, TS1, which lies 19.6 kcalmol(-1) below the sum of the energies of the reactants at 0 K. A four-membered ringlike transition structure TS2 of Cs symmetry, which lies 13.9 kcalmol(-1) above the energy of the separated reactants at 0 K, was also found for the concerted HO2* elimination from 1. An analysis of the electronic structures of TS1 and TS2 indicates that both modes of concerted HO2* elimination from 1 are better described as internal proton transfers than as intramolecular free-radical H-atom abstractions. The intramolecular 1,4-H-atom transfer in 1, which yields the alkoxy radical intermediate HOOCH2O*, takes place via a puckered ringlike transition structure TS3 that lies 13.7 kcalmol(-1) above the energy of the reactants at 0 K. In contrast with earlier studies suggesting that a direct H-atom abstraction mechanism might occur at high temperatures, we could not find any transition structure for direct H-atom transfer from the OH group of *CH2OH to the O2. The observed non-Arrhenius behavior of the temperature dependence of the rate constant for the gas-phase oxidation of *CH2OH is ascribed to the combined effect of the initial barrier-free formation of the *OO-CH2OH adduct with a substantial energy release and the existence of a low-barrier and two high-barrier pathways for its decomposition into CH2O and HO2*.

Point-dipole approximation of the exciton coupling model versus type of bonding and of excitons in porphyrin supramolecular structures.

The application of the exciton coupling model to interacting porphyrin chromophores is discussed. Covalently bonded systems and ionic or electrostatically bonded homoassociates require different orientations of the transition dipole moments in order to explain the experimental results: according to the symmetry of the assembly for covalently bonded porphyrins, and assuming isolated chromophores for ionic bonded porphyrins. Further, for covalently bonded systems, an extended exciton coupling has been demonstrated, but the ionic systems are in agreement with non-extended couplings. The relation of these facts to a molecular description of solid-state Wannier-Mott or Frenkel excitons is briefly discussed.

Tropospheric formation of hydroxymethyl hydroperoxide, formic acid, H2O2, and OH from carbonyl oxide in the presence of water vapor: a theoretical study of the reaction mechanism.

We have carried out a theoretical investigation of the gas-phase reaction mechanism of the H2COO+ H2O reaction, which is interesting for atmospheric purposes. The B3LYP method with the 6-31G(d,p) and 6-311 + G(2d,2p) basis sets was employed for the geometry optimization of the stationary points. Additionally, single-point CCSD(T)/6-311 + G(2d,2p) energy calculations have been done for the B3LYP/6-311 + G(2d,2p) optimized structures. The reaction begins with the formation of a hydrogen-bond complex that we have calculated to be 6 kcalmol(-1) more stable than the reactants. Then, the reaction follows two different channels. The first one leads to the formation of hydroxymethyl hydroperoxide (HMHP), for which we have calculated an activation barrier of deltaGa(298) = 11.3 kcalmol(-1), while the second one gives HCO + OH + H2O, with a calculated activation barrier of deltaGa(298) = 20.9 kcalmol(-1). This process corresponds to the water-catalyzed decomposition of H2COO, and its unimolecular decomposition has been previously reported in the literature. Additionally, we have also investigated the HMHP decomposition. We have found two reaction modes that yield HCOOH+H2O; one reaction mode leads to H2CO + H2O2 and a homolytic cleavage, which produces H2COOH + OH radicals. Furthermore, we have also investigated the water-assisted HMHP decomposition, which produces a catalytic effect of about 14 kcalmol(-1) in the process that leads to H2CO + H2O2.

IgG subclass deficiencies associated with bronchiectasis.

Only a small number of patients with IgG subclass deficiencies (IgGSD) have been observed to have bronchiectasis. Moreover, in the series of patients with bronchiectasis, IgGSD have not been found at any frequency, and the etiology of bronchiectasis remains unclear in 29 to 49% of cases. Serum concentrations of total IgG, IgA, and IgG subclasses as well as pulmonary function were measured in 65 patients (aged: 10 to 74 yr) with bronchiectasis of unknown etiology. An ELISA test was performed to quantify subclasses 1 through 4 using subclass-specific antihuman monoclonal antibodies. IgG subclass estimation in a healthy population with age-stratified normal ranges was derived from 100 adults, 37 children aged between 10 and 12 yr, and 27 adolescents aged between 13 and 16 yr. Serum concentrations of specific IgG antibodies to Haemophilus influenzae type b capsular polysaccharide (Hib-PRP) were also assayed by an ELISA test in 19 of the patients (10 with IgGSD and nine with non-IgGSD) and in 58 healthy individuals before and 3 wk after immunization with Hib-PRP conjugated to meningococcal outer membrane protein complex (OMPC). Thirty-one patients (48%) had low serum concentrations of one or more IgG subclasses (19 IgG2 deficiencies, 2 IgG3 deficiencies, 3 IgG4 deficiencies, and 7 combined subclass deficiencies). All patients showed increased levels of total IgG, IgG1, and IgA, but this rise was significantly higher in patients without IgGSD. Patients with IgGSD showed impaired antibody response to Hib-PRP compared with patients with non-IgGSD and the control group. IgGSD, particularly IgG2 deficiency, are not an unusual cause of bronchiectasis. Therefore, serum levels of IgG subclasses must be assayed whenever other causes of bronchiectasis have been ruled out.

Nasal continuous positive airway pressure with supplemental oxygen in coexistent sleep apnoea-hypopnoea syndrome and severe chronic obstructive pulmonary disease.

The objective of our study was to assess the application of nasal continuous positive airway pressure (nCPAP) with supplemental oxygen for correction of upper airway obstructive episodes and hypoxaemia during sleep in stable patients with sleep apnoea-hypopnoea syndrome (SAHS) and severe chronic obstructive pulmonary disease (COPD). Ten male patients with symptomatic SAHS and severe COPD (forced expiratory volume in one second < 50% of predicted) were studied for three consecutive nights. Diagnostic polysomnography was performed the first night and repeated with increasing nCPAP levels, with and without supplemental oxygen on the second and third nights, respectively. Diagnostic polysomnography showed: mean (SD) apnoea-hypopnoea index 41 (22) events.h-1; mean arterial oxygen saturation (Sa,O2) was 86 (2)% and mean desaturation nadir was 81 (4)% during non-rapid eye movement (nREM) sleep and 80 (7)% and 73 (9)%, respectively during REM sleep. The application of nCPAP during the second night corrected apnoeas and hypopnoeas, but mean Sa,O2 remained < 90% in all patients. With the addition of oxygen at a flow of 1.5 L.min-1 at suboptimal nCPAP levels, we observed an increase in apnoea frequency, persistence of apnoeas at nCPAP levels which eliminated them when no supplemental oxygen was administered, and longer duration of apnoeas and hypopnoeas. However, when the effective nCPAP level of the second night was reached with supplemental oxygen during the third night, its efficacy in eliminating apnoeas and hypopnoeas was maintained and, furthermore, all patients presented Sa,O2 > 90%, with no greater hypercapnia cardiac arrhythmias. We conclude that nasal continuous positive airway pressure with supplemental oxygen constitutes a practical therapeutic alternative for hypoxic patients with sleep apnoea-hypopnoea syndrome and chronic obstructive pulmonary disease.

Adult onset of nemaline myopathy presenting as respiratory insufficiency.

A 49-year-old woman was admitted to the hospital for hypercapnia. Pulmonary function testing showed small lung volumes without parenchymal lung disease. Muscle enzyme levels were normal and the EMG was nonspecific. Finally, muscle biopsy revealed abundant nemaline bodies characteristic of nemaline myopathy. Nasal intermittent pressure ventilation was started with a preset pressure ventilator during sleeping hours with a good response.

[Evaluation of replacement therapy in emphysema caused by alpha 1-antitrypsin deficiency]. / Evaluación del tratamiento sustitutivo del enfisema por déficit de alfa-1-antitripsina.

Assessment of alpha 1-antitrypsin replacement therapy (AAT) for emphysema. Patient characteristics were analyzed along with the possible side effects of the treatment and its efficacy in maintaining appropriate AAT blood levels. Lung function changes were also studied. The treatment protocol began with 4 weekly intravenous doses of 60 mg/kg AAT (Prolastin) and continued with monthly doses of 240 mg/kg. AAT serum levels were measured before each dose. Every 6 months pulmonary function tests (spirometry, plethysmography and CO transfer) were performed. Thirteen patients (mean age 46 yr) have been studied since 1988. Mean initial FEV1 was 0.79 l. Over 250 doses have been infused with no significant side effects reported. AAT levels before treatment in 3 patients were lower than that considered protective (50 mg/dl). Function tests results indicated stabilization of spirometric values in most cases. Diagnosis of AAT deficiency is delayed considerably, meaning that significant functional deterioration takes place before replacement therapy begins. No side effects of treatment have been observed. Until an appropriate interval between doses has been established, each patient's AAT levels must be monitored.