Systematic 1 Hz direct electrical stimulation for seizure induction: A reliable method for localizing seizure onset zone and predicting seizure freedom.

OBJECTIVE: To prospectively investigate the utility of seizure induction using systematic 1 Hz stimulation by exploring its concordance with the spontaneous seizure onset zone (SOZ) and relation to surgical outcome; comparison with seizures induced by non-systematic 50 Hz stimulation was attempted as well. METHODS: Prospective cohort study from 2018 to 2021 with ≥ 1 y post-surgery follow up at Yale New Haven Hospital. With 1 Hz, all or most of the gray matter contacts were stimulated at 1, 5, and 10 mA for 30-60s. With 50 Hz, selected gray matter contacts outside of the medial temporal regions were stimulated at 1-5 mA for 0.5-3s. Stimulation was bipolar, biphasic with 0.3 ms pulse width. The Yale Brain Atlas was used for data visualization. Variables were analyzed using Fisher's exact, χ2, or Mann-Whitney test. RESULTS: Forty-one consecutive patients with refractory epilepsy undergoing intracranial EEG for localization of SOZ were included. Fifty-six percent (23/41) of patients undergoing 1 Hz stimulation had seizures induced, 83% (19/23) habitual (clinically and electrographically). Eighty two percent (23/28) of patients undergoing 50 Hz stimulation had seizures, 65% (15/23) habitual. Stimulation of medial temporal or insular regions with 1 Hz was more likely to induce seizures compared to other regions [15/32 (47%) vs. 2/41 (5%), p < 0.001]. Sixteen patients underwent resection; 11/16 were seizure free at one year and all 11 had habitual seizures induced by 1 Hz; 5/16 were not seizure free at one year and none of those 5 had seizures with 1 Hz (11/11 vs 0/5, p < 0.0001). No patients had convulsions with 1 Hz stimulation, but four did with 50 Hz (0/41 vs. 4/28, p = 0.02). SIGNIFICANCE: Induction of habitual seizures with 1 Hz stimulation can reliably identify the SOZ, correlates with excellent surgical outcome if that area is resected, and may be superior (and safer) than 50 Hz for this purpose. However, seizure induction with 1 Hz was infrequent outside of the medial temporal and insular regions in this study.

Ecological Calendars, Food Sovereignty, and Climate Adaptation in Standing Rock.

Indigenous food sovereignty relies on ecological knowledge of plants and animals, including knowledge related to their development and behavior through the seasons. In the context of anthropogenic climate change, ecological calendars based on Indigenous knowledge may enable communities to anticipate seasonal phenomena. We conducted research with communities in the Standing Rock Nation (North and South Dakota, USA) to develop ecological calendars based on their ecological knowledge. We present ecological calendars developed in seven communities through a series of workshops and interviews. These calendars are rich with knowledge about temporal relations within each community's ecosystem, including the use of plants and animals as seasonal indicators and cues for food system activities. However, the calendars also reveal the impacts of cultural genocide wrought by the United States government in its efforts to colonize the lands and minds of Indigenous communities. Given the diversity of knowledge among Standing Rock communities, we identify opportunities for knowledge exchange to revitalize ecological relations at the heart of food sovereignty. We highlight the potential for ecological calendars to facilitate climate adaptation by enabling communities to synchronize their food systems with an increasingly variable climate.

High-resolution cortical parcellation based on conserved brain landmarks for localization of multimodal data to the nearest centimeter.

Precise cortical brain localization presents an important challenge in the literature. Brain atlases provide data-guided parcellation based on functional and structural brain metrics, and each atlas has its own unique benefits for localization. We offer a parcellation guided by intracranial electroencephalography, a technique which has historically provided pioneering advances in our understanding of brain structure-function relationships. We used a consensus boundary mapping approach combining anatomical designations in Duvernoy's Atlas of the Human Brain, a widely recognized textbook of human brain anatomy, with the anatomy of the MNI152 template and the magnetic resonance imaging scans of an epilepsy surgery cohort. The Yale Brain Atlas consists of 690 one-square centimeter parcels based around conserved anatomical features and each with a unique identifier to communicate anatomically unambiguous localization. We report on the methodology we used to create the Atlas along with the findings of a neuroimaging study assessing the accuracy and clinical usefulness of cortical localization using the Atlas. We also share our vision for the Atlas as a tool in the clinical and research neurosciences, where it may facilitate precise localization of data on the cortex, accurate description of anatomical locations, and modern data science approaches using standardized brain regions.

Photoelectron Spectroscopic and Computational Study of the Deprotonated Gallic Acid and Propyl Gallate Anions.

Antioxidants play important roles in eliminating reactive oxygen species (ROS), which have been associated with various degenerative diseases, such as cancer, aging, and inflammatory diseases. Gallic acid (GA) and propyl gallate (PG) are well-known antioxidants and have been widely studied in vitro and in vivo. The biological antioxidant abilities of GA and PG are related to the electronic structure of their dehydro-radicals. In this work, we report a combined photoelectron spectroscopic and computational study of the deprotonated gallic acid anion, [GA - H]-, and deprotonated propyl gallate anion, [PG - H]-. Adiabatic electron affinities of the dehydro-gallic acid radical, [GA - H]· and of the dehydro-propyl gallate radical, [PG - H]·, are measured to be 2.90 ± 0.05 eV and 2.85 ± 0.05 eV, respectively, and compared to computational results.

Photoelectron Spectroscopic Study of Ascorbate and Deprotonated Ascorbate Anions Using an Electrospray Ion Source and a Cryogenically Cooled Ion Trap.

Reactive oxygen species (ROS) in biological systems are formed through a variety of mechanisms. These species are very reactive and have been associated with many diseases, including cancer and cardiovascular disease. One way of removing ROS from the body is through the use of radical scavengers, which are compounds capable of giving up an electron to neutralize the ROS yet form a stable radical species themselves. A common radical scavenger is ascorbic acid, also known as vitamin C. At physiological pH, ascorbic acid is predominately present as the ascorbate anion, C6H7O6-. The ascorbate anion, as well as the dianion (C6H6O62-), is an effective antioxidant due to its ability to donate an electron from a lone pair generated by deprotonation. An electrospray ionization source was added to our pulsed anion photoelectron spectrometer to study ascorbate anions and deprotonated ascorbate dianions via photoelectron spectroscopy. The antioxidant behavior of the ascorbate anion and the deprotonated ascorbate dianion was confirmed based on the experimental vertical detachment energy (VDE), and, therefore, the ionization energy of the anions, 3.85 and 2.68 eV, respectively.

Study of the Reaction of Hydroxylamine with Iridium Atomic and Cluster Anions (n = 1-5).

Elucidating the multifaceted processes of molecular activation and subsequent reactions gives a fundamental view into the development of iridium catalysts as they apply to fuels and propellants, for example, for spacecraft thrusters. Hydroxylamine, a component of the well-known hydroxylammonium nitrate (HAN) ionic liquid, is a safer alternative and mimics the chemistry and performance standards of hydrazine. The activation of hydroxylamine by anionic iridium clusters, Irn- (n = 1-5), depicts a part of the mechanism, where two hydrogen atoms are removed, likely as H2, and Irn(NOH)- clusters remain. The significant photoelectron spectral differences between these products and the bare clusters illustrate the substantial electronic changes imposed by the hydroxylamine fragment on the iridium clusters. In combination with DFT calculations, a preliminary reaction mechanism is proposed, identifying the possible intermediate steps leading to the formation of Ir(NOH)-.

Intramolecular electron-induced proton transfer and its correlation with excited-state intramolecular proton transfer.

Electron-induced proton transfer depicts the proton motion coupled with the attachment of a low-energy electron to a molecule, which helps to understand copious fundamental chemical processes. Intramolecular electron-induced proton transfer is a similar process that occurs within a single molecule. To date, there is only one known intramolecular example, to the best of our knowledge. By studying the 10-hydroxybenzo[h]quinoline and 8-hydroxyquinoline molecules using anion photoelectron spectroscopy and density functional theory, and by theoretical screening of six other molecules, here we show the intramolecular electron-induced proton transfer capability of a long list of molecules that meanwhile have the excited-state intramolecular proton transfer property. Careful examination of the intrinsic electronic signatures of these molecules reveals that these two distinct processes should occur to the same category of molecules. Intramolecular electron-induced proton transfer could have potential applications such as molecular devices that are responsive to electrons or current.

The Impact of Musical Training on Hand Biomechanics in String Musicians.

Background: The effects of musical training on the body in professional musicians remain an understudied area, particularly in reference to understanding and managing orthopedic/neuromuscular deviations and injuries in this population. The purpose of this study was to evaluate hand/finger fine motor function in musicians via physical examination as well as laboratory-based evaluations. Methods: Thirteen healthy noninjured young elite string musicians participated in this study. Performance of musicians was compared with healthy age-matched, sex-matched, and handedness-matched nonmusician controls. Results: Musicians exhibited decreased intrinsic muscle strength compared with controls; however, no change in extrinsic muscle strength was found between groups. No between-group differences in overall force control were found; however, Group × Hand (right vs left) interactions were found in force control. Conclusions: These data suggest that musicians are a unique population with respect to: (1) fine motor control of the hand; and (2) exhibit changes in differential hand use. This suggests cortical reorganization of string musicians, such that this population should be studied separately from typical healthy controls with respect to hand function.

Childhood Adversities and Physical and Mental Health Outcomes in Adults Living with HIV: Findings from the Ontario HIV Treatment Network Cohort Study.

We sought to estimate the prevalence of childhood adversity and examine its relationship with health outcomes among people living with HIV. Study participants included 1409 adults living with HIV and receiving care in Toronto, Canada. Data on childhood adversity, health behaviors, HIV outcome measures, depression, and health-related quality of life (HRQOL) were collected through face-to-face interviews and medical records. Statistical analyses included multivariable linear and logistic regression modeling. The prevalence of any childhood adversity was 71% (individual types ranged from 11% to 44%) and higher prevalence was associated with younger age, Indigenous or African/Caribbean/Black ethnicity, lower socioeconomic status, and higher rates of cigarette smoking and nonmedicinal drug use. Greater number of childhood adversities was associated with greater odds of depression and decreasing mental HRQOL. HIV care providers need to screen for childhood adversities and address childhood trauma within the context of HIV care.

Impact of depression and recreational drug use on emergency department encounters and hospital admissions among people living with HIV in Ontario: A secondary analysis using the OHTN cohort study.

INTRODUCTION: Nearly half of HIV-positive patients experience mental health and substance use problems, but many do not receive adequate or ongoing mental health or addiction care. This lack of ongoing care can result in the use of costly acute care services. Prospective evaluations of the relationship between psychiatric and substance use disorders and acute care services use are lacking, and this information is needed to understand unmet needs and improve access to appropriate services. METHODS: We conducted a secondary data analysis from a multicenter, longitudinal, prospective cohort study (n = 3,482 adults) between October 1, 2007 and March 31, 2013. We used explanatory extended Cox proportional hazard regression models to examine the impact of current depression and recreational drug use on acute care services use, and to explore whether current depression and recreational drug use were associated with potentially avoidable acute care services use. RESULTS: Over our 5.5 year study period, HIV-positive participants with current depression-only (aHR [95% CI]:1.2[1.1-1.4]), recreational drug use-only (1.3[1.1-1.6]), or co-occurring depression and recreational drug use (1.4[1.2-1.7]) were associated with elevated hazard of emergency department (ED) encounters compared to participants without these conditions. Over half of ED encounters were potentially avoidable. Participants with current depression-only (1.3[1.1-1.5];1.3[1.03-1.6]), recreational drug use-only (1.3[1.04-1.6];1.5[1.1-1.9]), or co-occurring depression and recreational drug use (1.3[1.04-1.7];1.4[1.06-1.9]) were associated with elevated hazard of low-acuity or repeated ED encounters respectively. CONCLUSIONS: We found a significant increase in ED services use and potentially avoidable ED encounters (including low-acuity or repeated ED encounters), particularly among those with either current depression or recreational drug use. These findings emphasize the challenges in managing HIV and mental health/addiction co-morbidities in the current HIV care model. Future research should evaluate integrated and collaborative care programs for improving the coordination of care and effectively treat mental health and addiction problems among HIV-positive patients in Ontario.

High retention in HIV care at a tertiary care centre in Toronto, Canada.

Poor retention in HIV care is associated with poor clinical outcomes and mortality. Previous studies of predictors of poor retention have been conducted with a wide variety of populations, using different measures of retention, and occasionally have conflicting results. We studied demographic and psychosocial factors associated with inter-visit interval length in a setting of universal health care and modern cART. Patients attending ≥2 appointments with an HIV specialist at the Toronto General Hospital Immunodeficiency Clinic from 2004 to 2013 were studied. A sub-analysis included psychosocial measures from annual questionnaires for Ontario HIV Treatment Network Cohort Study (OCS) participants. Median inter-visit interval and constancy (percentage of 4-month intervals with ≥1 visit) were calculated by patient. Multivariable generalized estimating equation models identified factors associated with inter-visit interval length and intervals ≥12 months. 1591 patients were included. 615 patients completed an OCS questionnaire and were more likely to be older white MSM from Canada with a viral load (VL) <50 copies/ml. The median (IQR) of patients' median inter-visit intervals was 3.15 (2.78, 3.84) months and median (IQR) constancy was 90% (71%, 100%). Two percent of inter-visit intervals were ≥12 months and 25% of patients had ≥1 interval ≥12 months. Longer inter-visit intervals were associated with younger age, white race, earlier calendar year, longer duration of HIV, VL < 50 copies/mL and higher CD4 counts. Patients who were younger, white, had injection drug use as a risk factor, had a longer duration of HIV, and had VL ≥50 copies/mL were more likely to have an inter-visit interval ≥12 months. In the OCS sub-analysis including psychosocial variables, lower levels of depression were associated with longer inter-visit intervals. Retention at this tertiary care centre was high. Efforts to maximize attendance should focus on younger patients and those with substance abuse issues.

Prevalence, Recurrence, and Incidence of Current Depressive Symptoms among People Living with HIV in Ontario, Canada: Results from the Ontario HIV Treatment Network Cohort Study.

INTRODUCTION: Current studies of depression among people living with HIV focus on describing its point prevalence. Given the fluctuating nature of depression and its profound impacts on clinical and quality-of-life outcomes, this study aimed to examine the prevalence, recurrence and incidence of current depressive symptoms and its underlying catalysts longitudinally and systematically among these individuals. METHODS: We conducted a prospective cohort study between October 1, 2007 and December 31, 2012 using longitudinal linked data sources. Current depressive symptoms was identified using the Centre for Epidemiologic Studies Depression Scale or the Kessler Psychological Distress Scale, first at baseline and again during follow-up interviews. Multivariable regressions were used to characterize the three outcomes. RESULTS: Of the 3,816 HIV-positive participants, the point prevalence of depressive symptoms was estimated at 28%. Of the 957 participants who were identified with depressive symptoms at baseline and who had at least two years of follow-up, 43% had a recurrent episode. The cumulative incidence among 1,745 previously depressive symptoms free participants (at or prior to baseline) was 14%. During the five-year follow-up, our multivariable models showed that participants with greater risk of recurrent cases were more likely to feel worried about their housing situation. Participants at risk of developing incident cases were also likely to be younger, gay or bisexual, and unable to afford housing-related expenses. CONCLUSIONS: Depressive symptoms are prevalent and likely to recur among people living with HIV. Our results support the direction of Ontario's HIV/AIDS Strategy to 2026, which addresses medical concerns associated with HIV (such as depression) and the social drivers of health in order to enhance the overall well-being of people living with or at risk of HIV. Our findings reinforce the importance of providing effective mental health care and demonstrate the need for long-term support and routine management of depression, particularly for individuals at high risk.

Adequacy of Mental Health Services for HIV-Positive Patients with Depression: Ontario HIV Treatment Network Cohort Study.

BACKGROUND: Major depression can profoundly impact clinical and quality-of-life outcomes of people living with HIV, and this disease is underdiagnosed and undertreated in many HIV-positive individuals. Here, we describe the prevalence of publicly funded primary and secondary mental health service use and antidepressant use, as well as mental health care for depression in accordance with existing Canadian guidelines for HIV-positive patients with depression in Ontario, Canada. METHODS: We conducted a prospective cohort study linking data from the Ontario HIV Treatment Network Cohort Study with administrative health databases in the province of Ontario, Canada. Current depression was assessed using the Center for Epidemiologic Depression Scale or the Kessler Psychological Distress Scale. Multivariable regressions were used to characterize prevalence outcomes. RESULTS: Of 990 HIV-positive patients with depression, 493 (50%) patients used mental health services; 182 (18%) used primary services (general practitioners); 176 (18%) used secondary services (psychiatrists); and 135 (14%) used both. Antidepressants were used by 407 (39%) patients. Patients who identified as gay, lesbian, or bisexual, as having low income or educational attainment, or as non-native English speakers or immigrants to Canada were less likely to obtain care. Of 493 patients using mental health services, 250 (51%) received mental health care for depression in accordance with existing Canadian guidelines. CONCLUSIONS: Our results showed gaps in delivering publicly funded mental health services to depressed HIV-positive patients and identified unequal access to these services, particularly among vulnerable groups. More effective mental health policies and better access to mental health services are required to address HIV-positive patient needs and reduce depression's impact on their lives.

Validation of Six Short and Ultra-short Screening Instruments for Depression for People Living with HIV in Ontario: Results from the Ontario HIV Treatment Network Cohort Study.

OBJECTIVE: Major depression affects up to half of people living with HIV. However, among HIV-positive patients, depression goes unrecognized 60-70% of the time in non-psychiatric settings. We sought to evaluate three screening instruments and their short forms to facilitate the recognition of current depression in HIV-positive patients attending HIV specialty care clinics in Ontario. METHODS: A multi-centre validation study was conducted in Ontario to examine the validity and accuracy of three instruments (the Center for Epidemiologic Depression Scale [CESD20], the Kessler Psychological Distress Scale [K10], and the Patient Health Questionnaire depression scale [PHQ9]) and their short forms (CESD10, K6, and PHQ2) in diagnosing current major depression among 190 HIV-positive patients in Ontario. Results from the three instruments and their short forms were compared to results from the gold standard measured by Mini International Neuropsychiatric Interview (the "M.I.N.I."). RESULTS: Overall, the three instruments identified depression with excellent accuracy and validity (area under the curve [AUC]>0.9) and good reliability (Kappa statistics: 0.71-0.79; Cronbach's alpha: 0.87-0.93). We did not find that the AUCs differed in instrument pairs (p-value>0.09), or between the instruments and their short forms (p-value>0.3). Except for the PHQ2, the instruments showed good-to-excellent sensitivity (0.86-1.0) and specificity (0.81-0.87), excellent negative predictive value (>0.90), and moderate positive predictive value (0.49-0.58) at their optimal cut-points. CONCLUSION: Among people in HIV care in Ontario, Canada, the three instruments and their short forms performed equally well and accurately. When further in-depth assessments become available, shorter instruments might find greater clinical acceptance. This could lead to clinical benefits in fast-paced speciality HIV care settings and better management of depression in HIV-positive patients.

Importance of Time Scale and Local Environment in Electron-Driven Proton Transfer. The Anion of Acetoacetic Acid.

Anion photoelectron spectroscopy (PES) and electron energy-loss spectroscopy (EELS) probe different regions of the anionic potential energy surface. These complementary techniques provided information about anionic states of acetoacetic acid (AA). Electronic structure calculations facilitated the identification of the most stable tautomers and conformers for both neutral and anionic AA and determined their relative stabilities and excess electron binding energies. The most stable conformers of the neutral keto and enol tautomers differ by less than 1 kcal/mol in terms of electronic energies corrected for zero-point vibrations. Thermal effects favor these conformers of the keto tautomer, which do not support an intramolecular hydrogen bond between the keto and the carboxylic groups. The valence anion displays a distinct minimum which results from proton transfer from the carboxylic to the keto group; thus, we name it an ol structure. The minimum is characterized by a short intramolecular hydrogen bond, a significant electron vertical detachment energy of 2.38 eV, but a modest adiabatic electron affinity of 0.33 eV. The valence anion was identified in the anion PES experiments, and the measured electron vertical detachment energy of 2.30 eV is in good agreement with our computational prediction. We conclude that binding an excess electron in a π* valence orbital changes the localization of a proton in the fully relaxed structure of the AA(-) anion. The results of EELS experiments do not provide evidence for an ultrarapid proton transfer in the lowest π* resonance of AA(-), which would be capable of competing with electron autodetachment. This observation is consistent with our computational results, indicating that major gas-phase conformers and tautomers of neutral AA do not support the intramolecular hydrogen bond that would facilitate ultrarapid proton transfer and formation of the ol valence anion. This is confirmed by our vibrational EELS spectrum. Anions formed by vertical electron attachment to dominant neutrals undergo electron autodetachment with or without vibrational excitations but are unable to relax to the ol structure on a time scale fast enough to compete with autodetachment.

Radial ridge excision for symptomatic volar tendon subluxation following de Quervain's release.

Traditional surgical release to address de Quervain's stenosing tenosynovitis can lead to the rare complication of volar tendon subluxation. This study presents a surgical procedure, which entails excision of the radial ridge as an alternative treatment to relieve pain associated with symptomatic volar tendon subluxation following de Quervain's release. The procedure was performed on 6 patients complaining of painful volar tendon subluxation of abductor pollicis longus (APL) and extensor pollicis brevis (EPB), following a first dorsal compartment release and postoperative splinting. We opened the same incision sharply, with direct view of the tendons of the first dorsal compartment. The wrist was ranged through extension and flexion, and volar subluxation of the APL and EPB over the prominent radial ridge was confirmed. The bony portion of the radial ridge was excised and filed smooth. The periosteal flap is advanced over the ridge and sutured into place. The APL and EPB tendons were released from dorsal retractors. All patients reported relief upon follow-up. Excision of this ridge removes the obtrusive friction to the APL and EPB tendons, allowing them to glide painlessly over the radial styloid.

Challenges to the involvement of people living with HIV in community-based HIV/AIDS organizations in Ontario, Canada.

The Greater Involvement of People Living with HIV/AIDS Principle (GIPA) has been a core commitment for many people involved in the community-based HIV/AIDS movement. GIPA refers to the inclusion of people living with HIV/AIDS in service delivery and decision-making processes that affect their lives. Despite its central importance to the movement, it has received little attention in the academic literature. Drawing on focus group discussions among staff members and volunteers of AIDS service organizations, activists, and community members, we explore challenges to the implementation of the GIPA principle in community-based HIV/AIDS organizations in Ontario, Canada. Our findings reveal ways in which implementing GIPA has become more complicated over recent years. Challenges relating to health, stigma and disclosure, evolving HIV/AIDS organizations, and GIPA-related tensions are identified. This paper considers our findings in light of previous research, and suggests some implications for practice.

Communication: In search of four-atom chiral metal clusters.

A combined study utilizing anion photoelectron spectroscopy and density functional theory was conducted to search for four-atom, chiral, metal, and mostly metal clusters. The clusters considered were AuCoMnBi(-/0), AlAuMnO(-/0), AgMnOAl(-/0), and AuAlPtAg(-/0), where the superscripts, (-/0), refer to anionic and neutral cluster species, respectively. Based on the agreement of experimentally and theoretically determined values of both electron affinities and vertical detachment energies, the calculated cluster geometries were validated and examined for chirality. Among both anionic and neutral clusters, five structures were identified as being chiral.

Negative ions of p-nitroaniline: photodetachment, collisions, and ab initio calculations.

The structures of parent anion, M(-), and deprotonated molecule, [M-H](-), anions of the highly polar p-nitroaniline (pNA) molecule are studied experimentally and theoretically. Photoelectron spectroscopy (PES) of the parent anion is employed to estimate the adiabatic electron affinity (EAa = 0.75 ± 0.1 eV) and vertical detachment energy (VDE = 1.1 eV). These measured energies are in good agreement with computed values of 0.73 eV for the EAa and the range of 0.85 to 1.0 eV for the VDE at the EOM-CCSD∕Aug-cc-pVTZ level. Collision induced dissociation (CID) of deprotonated pNA, [pNA - H](-), with argon yielded [pNA - H - NO](-) (i.e., rearrangement to give loss of NO) with a threshold energy of 2.36 eV. Calculations of the energy difference between [pNA - H](-) and [pNA - H - NO](-) give 1.64 eV, allowing an estimate of a 0.72 eV activation barrier for the rearrangement reaction. Direct dissociation of [pNA - H](-) yielding NO2(-) occurs at a threshold energy of 3.80 eV, in good agreement with theory (between 3.39 eV and 4.30 eV). As a result of the exceedingly large dipole moment for pNA (6.2 Debye measured in acetone), we predict two dipole-bound states, one at ~110 meV and an excited state at 2 meV. No dipole-bound states are observed in the photodetachment experiments due the pronounced mixing between states with dipole-bound and valence character similar to what has been observed in other nitro systems. For the same reason, dipole-bound states are expected to provide highly efficient "doorway states" for the formation of the pNA(-) valence anion, and these states should be observable as resonances in the reverse process, that is, in the photodetachment spectrum of pNA(-) near the photodetachment threshold.

Photoelectron spectroscopy of the aluminum hydride anions: AlH2(-), AlH3(-), Al2H6(-), Al3H9(-), and Al4H12(-).

We report measurements of the negative ion photoelectron spectra of the simple aluminum hydride anions: AlH2(-), AlH3(-), Al2H6(-), Al3H9(-), and Al4H12(-). From these spectra, we measured the vertical detachment energies of the anions, and we estimated the electron affinities of their neutral counterparts. Our results for AlH2(-), AlH3(-), and Al2H6(-) were also compared with previous predictions by theory.