Comprehensive Study of HCN: Potential Energy Surfaces, State-to-State Kinetics, and Master Equation Analysis.

Understanding the kinetics of the HCN system is critical to several disciplines in science and engineering, including interstellar chemistry, atmospheric reentry, and combustion, to name a few. This paper constructs a rovibrational state-specific kinetic mechanism for the HCN system, leveraging electronic structure calculations, classical scattering dynamics, and state-to-state kinetics. To this aim, three accurate potential energy surfaces (PESs), ', ', and ″, are constructed using multireference configuration interaction (MRCI) calculations for a comprehensive arrangement of the nuclei.

Carbon Clusters: Thermochemistry and Electronic Structure at High Temperatures.

This paper studies the thermochemistry and electronic structure of small carbon clusters and hydrocarbons, which are major constituents of pyrolysis gases released into the boundary layer of ablating heat shields. Our focus lies on clusters of up to four carbon atoms. Among other molecules, thermochemistry data for molecules such as CH and CH have been determined using the Weizmann-1 (W1) method.

Comparison of potential energy surfaces and computed rate coefficients for N dissociation.

Comparisons are made between potential energy surfaces (PES) for N + N and N + N collisions and between rate coefficients for N dissociation that were computed using the quasiclassical trajectory method (QCT) on these PESs. For N + N we compare the Laganà's empirical LEPS surface with one from NASA Ames Research Center based on quantum chemistry calculations. For N + N we compare two PESs (from NASA Ames and from the University of Minnesota).

Assessment and management of agitation in psychiatry: Expert consensus.

Background: Psychomotor agitation is associated with different psychiatric conditions and represents an important issue in psychiatry. Current recommendations on agitation in psychiatry are not univocal. Actually, an improper assessment and management may result in unnecessary coercive or sedative treatments.

Rovibrational internal energy transfer and dissociation of N2(1Σg+)-N(4S(u)) system in hypersonic flows.

A rovibrational collisional model is developed to study energy transfer and dissociation of N(2)((1)Σ(g)(+)) molecules interacting with N((4)S(u)) atoms in an ideal isochoric and isothermal chemical reactor. The system examined is a mixture of molecular nitrogen and a small amount of atomic nitrogen. This mixture, initially at room temperature, is heated by several thousands of degrees Kelvin, driving the system toward a strong non-equilibrium condition.

Theoretical calculation of jet fuel thermochemistry. 1. Tetrahydrodicylopentadiene (JP10) thermochemistry using the CBS-QB3 and G3(MP2)//B3LYP methods.

High-level ab initio calculations have been performed on the exo and endo isomers of gas-phase tetrahydrodicyclopentadiene (THDCPD), a principal component of the jet fuel JP10, using the Gaussian G(x) and G(x)(MP(x)) composite methods, as well as the CBS-QB3 method, and using a variety of isodesmic and homodesmotic reaction schemes. The impetus for this work is to help resolve large discrepancies existing between literature measurements of the formation enthalpy Delta(f)H degrees (298) for exo-THDCPD. We find that use of the isodesmic bond separation reaction C(10)H(16) + 14CH(4) --> 12C(2)H(6) yields results for the exo isomer (JP10) in between the two experimentally accepted values, for the composite methods G3(MP2), G3(MP2)//B3LYP, and CBS-QB3.

ECT in the treatment of a patient with catatonia: consent and complications.

Acute catatonia in an adolescent or young adult can present complex clinical challenges. Prominent issues include those involving diagnosis, timely and effective treatment, and diminished capacity to provide consent. The authors describe a 19-year-old woman presenting initially with manic excitement followed by a lengthy period of mutism, immobility, and food and fluid refusal.

Problems in Maintenance ECT in Bipolar Disorder: Replacement by Lithium and Anticonvulsants.

The authors describe three elderly patients whose electroconvulsive therapy (ECT) was characterized by protracted and unsatisfactory courses and frequent relapse. Sustained improvement resulted from the discontinuation of maintenance ECT and continuation of pharmacotherapy with combinations of lithium and carbamazepine or valproic acid. The patients are compared to a more typical patient with bipolar disorder who was successfully treated with long-term maintenance ECT.

Maintenance ECT in Coexisting Affective and Neurologic Disorders.

To the numerous reports of the safety and efficacy of electroconvulsive therapy (ECT) in acute depressive episodes in patients with coexisting neurologic illness, the authors report their experience with two patients treated with maintenance ECT for more than 2 years. The authors find maintenance ECT useful in ameliorating the depressive illness without worsening the neurologic illness.