Measuring the unmet needs of American military Veterans and their caregivers: Survey protocol of the HERO CARE survey.

BACKGROUND: Empowering Veterans to age in place is a Department of Veterans Affairs priority. Family or unpaid caregivers play an important role in supporting Veterans to achieve this goal. Effectively meeting the needs of Veterans and caregivers requires identifying unmet needs and relevant gaps in resources to address those needs. METHODS: Using a modified Socio-Ecological Model, we developed a prospective longitudinal panel design survey. We randomly selected 20,000 community-dwelling Veterans enrolled in the Veterans Health Administration (VHA), across five VHA sites. We oversampled Veterans with a higher predicted 2-year long-term institutional care (LTIC) risk. Veterans were mailed a packet containing a Veteran survey and a caregiver survey, to be answered by their caregiver if they had one. The Veteran survey assessed the following health-related domains: physical, mental, social determinants of health, and caregiver assistance. Caregivers completed questions regarding their demographic factors, caregiving activities, impact of caregiving, use of VA and non-VA services, and caregiver support resources. Follow-up surveys will be repeated twice at 12-month intervals for the same respondents. This article describes the HERO CARE survey protocol, content, and response rates. RESULTS: We received responses from 8,056 Veterans and 3,579 caregivers between July 2021 and January 2022, with 95.6% being received via mail. Veteran respondents were mostly males (96.5%), over 65 years of age (94.9%), married (55.0%), Non-Hispanic White (75.2%), and residing in urban areas (80.7%). CONCLUSIONS: This longitudinal survey is unique in its comprehensive assessment of domains relevant to older Veterans stratified by LTIC risk and their caregivers, focusing on social determinants, caregiver support, and the use of caregiver support resources. Survey data will be linked to Centers for Medicare & Medicaid Services and VA data. The results of this study will inform better planning of non-institutional care services and policy for Veterans and their caregivers.

Buprenorphine use and courses of care for opioid use disorder treatment within the Veterans Health Administration.

BACKGROUND: Retention of patients in buprenorphine medication treatment for opioid use disorder (B-MOUD) reduces harms associated with opioid use disorder (OUD). We sought to characterize the patients receiving B-MOUD and courses of B-MOUD in a large healthcare system. METHODS: We conducted a retrospective, open cohort study of patients with OUD who either did or did not receive B-MOUD courses within the Veterans Health Administration (VHA) from January 2006 through July 2019, using VHA clinical data. We compared patients receiving or not receiving B-MOUD, characterized B-MOUD courses (e.g., length and doses), and examined persistence, across patient characteristics, over time. We used analyses for normally or non-normally distributed continuous variables, categorical data, and persistence over time (Kaplan-Meier persistence curves). RESULTS: We identified 255,726 Veterans with OUD; 40,431 (15.8%) had received 63,929 B-MOUD courses. Compared to patients with OUD without B-MOUD, patients with B-MOUD were younger, more often of white race, and had more co-morbidities. The frequency of new B-MOUD starts and prevalent B-MOUD patients ranged from 1550 and 1989 in 2007 to 8146 and 16,505 in 2018, respectively. The median duration of B-MOUD was 157 (IQR: 37-537) days for all courses and 33.8% patients had more than one course. The average proportion days covered was 90% (SD: 0.15), and the average prescribed daily dose was 13.44 (SD: 6.5). CONCLUSIONS: Within a VHA B-MOUD cohort, courses increased more than 10-fold from 2006 to 2016 with nearly half of patients experiencing multiple courses. Patient demographics seem to dictate the length of courses.

Association between specific unmet functional needs and desire to institutionalize among caregivers of older veterans.

OBJECTIVES: To evaluate the associations between specific functional needs of older Veterans and the desire to institutionalize (DTI) among their caregivers. METHODS: Cross-sectional multivariable logistic regression analysis of 3579 Hero Care survey responses from caregivers of Veterans at five US sites from July to December 2021. Unmet needs were areas in which the caregiver reported the Veteran needed a little more or a lot more help. Caregiver DTI was defined as the caregiver reporting that they had discussed, considered, or taken steps toward a nursing home or assisted living placement for the Veteran or that they felt the Veteran would be better off in such a setting or they were likely to move the Veteran to another living arrangement. RESULTS: Caregivers were largely white, retired, females with an average age of 71 and with some college education who spent an average of 8-9 h per day 6 days a week caring for a Veteran spouse. There was evidence of associations between the following needs and a DTI: managing incontinence, using the telephone, transportation, and arranging services in the home such as visiting nurses, home care aides, or meals on wheels. Unmet functional needs in other selected domains were not associated with the DTI. CONCLUSION: Among caregivers of older Veterans, a need for more assistance managing incontinence, telephone use, transportation, and arranging in-home services were associated with the DTI. These may represent functional markers of important clinical determinants for institutionalization as well as potential targets for intervention to reduce caregiver DTI, such as programs that provide more caregiver or Veteran support in the home to meet these needs and reduce caregiver burden.

The COVID Season: U.S. Collegiate Esports Programs' Material Challenges and Opportunities During the 2020-21 Pandemic.

During the COVID-19 pandemic, universities were among the first institutions to shift to an online model. As they did so, nascent collegiate esports program lost access to campus spaces and in-person connections, potentially destabilizing this rising industry. Conversely, universities also worked to provide students remote access to resources, and many components of esports already occur online. Therefore, collegiate esports may have adjusted to distancing measures, potentially strengthening their footholds on US campuses. This paper draws on in-depth interviews with collegiate esports players, student employees, program directors, and administrators to address different programs' reactions to the pandemic, specifically the challenges and opportunities they faced. Overall, interviews reveal how COVID-19 shifted the understandings of and practices around gaming and esports, highlighted the intermittent relationship of online and offline spheres, and presented various possibilities and challenges for different stakeholders during the global pandemic.

Heart Failure Hospitalization Risk associated with Iron Status in Veterans with CKD.

BACKGROUND AND OBJECTIVES: CKD is an independent risk factor for heart failure. Iron dysmetabolism potentially contributes to heart failure, but this relationship has not been well characterized in CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We performed a historical cohort study using data from the Veterans Affairs Corporate Data Warehouse to evaluate the relationship between iron status and heart failure hospitalization. We identified a CKD cohort with at least one set of iron indices between 2006 and 2015. The first available date of serum iron indices was identified as the study index date. The cohort was divided into four iron groups on the basis of the joint quartiles of serum transferrin saturation (shown in percent) and ferritin (shown in nanograms per milliliter): reference (16%-28%, 55-205 ng/ml), low iron (0.4%-16%, 0.9-55 ng/ml), high iron (28%-99.5%, 205-4941 ng/ml), and function iron deficiency (0.8%-16%, 109-2783 ng/ml). We compared 1-year heart failure hospitalization risk between the iron groups using matching weights derived from multinomial propensity score models and Poisson rate-based regression. RESULTS: A total of 78,551 veterans met the eligibility criteria. The covariates were well balanced among the iron groups after applying the propensity score weights (n=31,819). One-year adjusted relative rate for heart failure hospitalization in the iron deficiency groups were higher compared with the reference group (low iron: 1.29 [95% confidence interval, 1.19 to 1.41]; functional iron deficiency: 1.25 [95% confidence interval, 1.13 to 1.37]). The high-iron group was associated with lower 1-year relative rate of heart failure hospitalization (0.82; 95% confidence interval, 0.72 to 0.92). Furthermore, the association between iron deficiency and heart failure hospitalization risk remained consistent regardless of the diabetes status or heart failure history at baseline. CONCLUSIONS: Iron deficiency, regardless of cause, was associated with higher heart failure hospitalization risk in CKD. Higher iron status was associated with lower heart failure hospitalization risks.

Peri-implantation intercourse does not lower fecundability.

STUDY QUESTION: Does sexual intercourse in the implantation time window (5-9 days after ovulation) reduce fecundability? SUMMARY ANSWER: After adjustment for intercourse in the fecund window and clustering by couple, there was no association between intercourse in the implantation time window and fecundity. WHAT IS KNOWN ALREADY: Previous research has suggested an association between intercourse in the peri-implantation time window (5-9 days after estimated ovulation) and reduced fecundability. STUDY DESIGN, SIZE, DURATION: We used data from the FERTILI study, a prospective observational study conducted in five European countries, with data collected from 1992 to 1996. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women who were experienced in fertility awareness tracking kept a daily diary of cervical mucus observations, basal body temperature measurements, coitus and clinically identified pregnancy. We estimated the day of ovulation as cycle length minus 13 days. From 661 women, 2606 cycles had intercourse during the fecund window (from 5 days before to 3 days after the estimated day of ovulation), resulting in 418 pregnancies (conception cycles). An established Bayesian fecundability model was used to estimate the fecundability ratio (FR) of peri-implantation intercourse on fecundability, while adjusting for each partner's age, prior pregnancy, the couple's probability of conception and intercourse pattern(s). We conducted sensitivity analyses estimating ovulation as cycle length minus 12 days, or alternatively, as the peak day of estrogenic cervical mucus. MAIN RESULTS AND THE ROLE OF CHANCE: There was no effect of peri-implantation intercourse on fecundability: adjusted FR for three or more acts of peri-implantation intercourse versus none: 1.00, 95% credible interval: 0.76-1.13. Results were essentially the same with sensitivity analyses. There was an inverse relationship between frequency of intercourse in the fecund window and intercourse in the peri-implantation window. LIMITATIONS, REASONS FOR CAUTION: Women with known subfertility were excluded from this study. Many couples in the study were avoiding pregnancy during much of the study, so 61% of otherwise eligible cycles in the database were not at meaningful risk of pregnancy and did not contribute to the analysis. Some couples may not have recorded all intercourse. WIDER IMPLICATIONS OF THE FINDINGS: We believe the current balance of evidence does not support a recommendation for avoiding intercourse in the peri-implantation period among couples trying to conceive. STUDY FUNDING/COMPETING INTEREST(S): No external funding. The authors have no potential competing interests. TRIAL REGISTRATION NUMBER: N/A.

Real-world management of hyperkalemia with patiromer among United States Veterans.

Objective: Patiromer is a sodium-free, non-absorbed, potassium (K+) binder approved for the treatment of hyperkalemia (HK). Among US Veterans with HK, this retrospective, observational cohort study evaluated patiromer utilization, RAASi continuation, and K+ concentration change following patiromer initiation.Methods: Using data from the Veterans Affairs Corporate Data Warehouse, Veterans with HK (K+ ≥5.1 mmol/L) were included upon patiromer initiation (index date) during the study period (1/2016-8/2018). All patients had heart failure (HF), diabetes, or chronic kidney disease (CKD). Patients with end-stage renal disease were excluded. The following outcomes were assessed within 6-months post-patiromer initiation: patiromer utilization (using proportion of days covered); K+ concentration change (pre- vs post-initiation); and RAASi continuation.Results: 288 Veterans with HK were included. Baseline characteristics were: median age 70 years, African-American race 24%, diabetes 83%, HF 32%, CKD 95%, and median K+ concentration 5.7 mmol/L. At 1, 3, and 6 months post-index, the median patiromer PDC was 100%, 66%, and 44%, respectively. K+ concentration reductions post-patiromer initiation were, on average, - 1.0 mmol/L (P < 0.001). At 3-6 months, 71% of patiromer initiators had K+ <5.1 mmol/L and 95% had K+ <5.5 mmol/L. RAASi therapy was continued in >80%-90% of patiromer-treated patients.Conclusions: The real-world utilization results suggest patiromer is used for the chronic management of HK. Clinically relevant K+ concentration reductions were observed at all study time points. The successful management of HK may have contributed to the observed high rate of RAASi therapy continuation. Further research is warranted to corroborate and extend these findings.

A Systematic Review of In Vitro and In Vivo Radio Frequency Exposure Methods.

Recently, interest in the effects of radio frequency (RF) on biological systems has increased and is partially due to the advancements and increased implementations of RF into technology. As research in this area has progressed, the reliability and reproducibility of the experiments has not crossed multidisciplinary boundaries. Therefore, as researchers, it is imperative to understand the various exposure systems available as well as the aspects, both electromagnetic and biological, needed to produce a sound exposure experiment. This systematic review examines common RF exposure methods for both in vitro and in vivo studies. For in vitro studies, possible biological limitations are emphasized. The validity of the examined methods, for both in vitro and in vivo, are analyzed by considering the advantages and disadvantages of each. This review offers guidance for researchers to assist in the development of an RF exposure experiment that crosses current multidisciplinary boundaries.

Identification of Axial Spondyloarthritis Patients in a Large Dataset: The Development and Validation of Novel Methods.

OBJECTIVE: Observational axial spondyloarthritis (axSpA) research in large datasets has been limited by a lack of adequate methods for identifying patients with axSpA, because there are no billing codes in the United States for most subtypes of axSpA. The objective of this study was to develop methods to accurately identify patients with axSpA in a large dataset. METHODS: The study population included 600 chart-reviewed veterans, with and without axSpA, in the Veterans Health Administration between January 1, 2005, and June 30, 2015. AxSpA identification algorithms were developed with variables anticipated by clinical experts to be predictive of an axSpA diagnosis [demographics, billing codes, healthcare use, medications, laboratory results, and natural language processing (NLP) for key SpA features]. Random Forest and 5-fold cross validation were used for algorithm development and testing in the training subset (n = 451). The algorithms were additionally tested in an independent testing subset (n = 149). RESULTS: Three algorithms were developed: Full algorithm, High Feasibility algorithm, and Spond NLP algorithm. In the testing subset, the areas under the curve with the receiver-operating characteristic analysis were 0.96, 0.94, and 0.86, for the Full algorithm, High Feasibility algorithm, and Spond NLP algorithm, respectively. Algorithm sensitivities ranged from 85.0% to 95.0%, specificities from 78.0% to 93.6%, and accuracies from 82.6% to 91.3%. CONCLUSION: Novel axSpA identification algorithms performed well in classifying patients with axSpA. These algorithms offer a range of performance and feasibility attributes that may be appropriate for a broad array of axSpA studies. Additional research is required to validate the algorithms in other cohorts.

VA Geriatric Scholars Program's impact on prescribing potentially inappropriate medications.

OBJECTIVES: The Veterans Affairs (VA) Geriatric Scholars Program (GSP) is a workforce development program to enhance skills and competencies among VA clinicians who provide healthcare for older veterans in VA primary care clinics. An intensive geriatrics didactics (IGD) course is a core element of this professional development program. The objective of this study was to evaluate the impact of completing the IGD course on providers' rates of prescribing definite potentially inappropriate medications (DPIMs) based on Beers Criteria from 2008 to 2016. STUDY DESIGN: We applied a longitudinal interrupted time series design to examine changes in DPIM prescribing rates for GSP participants before and after completing the IGD course. METHODS: The time series was divided into two 12-month periods, representing the preintervention period (ie, 12 months prior to completing the IGD course) and the postintervention period (ie, 12 months after completing the IGD course), and populated with pharmacy dispensing data from the VA's Corporate Data Warehouse. An adjusted slope impact model was developed to estimate the postintervention change in the proportion of the dispensed medications identified as DPIMs. RESULTS: After adjusting for case mix, we observed a statistically significant reduction in the proportion of DPIMs dispensed post IGD (slope change, 0.994; 95% CI, 0.991-0.997). This change in slope reflects a total decrease of 7971 DPIM dispensings during the postintervention period. This equates to an estimated 24 fewer DPIM dispensings per provider during the postintervention period. CONCLUSIONS: Although the size of the effect was modest, we found that participation in the GSP IGD course reduced prescribing of DPIMs for older veterans.

Validation of Algorithms Used to Identify Red Blood Cell Transfusion Related Admissions in Veteran Patients with End Stage Renal Disease.

BACKGROUND: The goal of this study was to compare the performance of several database algorithms designed to identify red blood cell (RBC) Transfusion Related hospital Admissions (TRAs) in Veterans with end stage renal disease (ESRD). METHODS: Hospitalizations in Veterans with ESRD and evidence of dialysis between 01/01/2008 and 12/31/2013 were screened for TRAs using a clinical algorithm (CA) and four variations of claims-based algorithms (CBA 1-4). Criteria were implemented to exclude patients with non-ESRD-related anemia (e.g., injury, surgery, bleeding, medications known to produce anemia). Diagnostic performance of each algorithm was delineated based on two clinical representations of a TRA: RBC transfusion required to treat ESRD-related anemia on admission regardless of the reason for admission (labeled as TRA) and hospitalization for the primary purpose of treating ESRD-related anemia (labeled TRA-Primary). The performance of all algorithms was determined by comparing each to a reference standard established by medical records review. Population-level estimates of classification agreement statistics were calculated for each algorithm using inverse probability weights and bootstrapping procedures. Due to the low prevalence of TRAs, the geometric mean was considered the primary measure of algorithm performance. RESULTS: After application of exclusion criteria, the study consisted of 12,388 Veterans with 26,672 admissions. The CA had a geometric mean of 90.8% (95% Confidence Interval: 81.8, 95.6) and 94.7% (95% CI: 80.5, 98.7) for TRA and TRA-Primary, respectively. The geometric mean for the CBAs ranged from 60.3% (95% CI: 53.2, 66.9) to 91.8% (95% CI: 86.9, 95) for TRA, and from 80.7% (95% CI: 72.9, 86.7) to 96.7% (95% CI: 94.1, 98.2) for TRA-Primary. The adjusted proportions of admissions classified as TRAs was 3.2% (95% CI: 2.8, 3.8) and TRA-Primary was 1.3% (95% CI: 1.1, 1.7). CONCLUSIONS: The CA and select CBAs were able to identify TRAs and TRA-primary with high levels of accuracy and can be used to examine anemia management practices in ESRD patients.

An increased mortality risk is associated with abnormal iron status in diabetic and non-diabetic Veterans with predialysis chronic kidney disease.

Iron parameters have not been well characterized in pre-dialysis patients with chronic kidney disease (CKD), and it remains unclear if abnormal iron balance is associated with increased mortality. Therefore, we performed a historical cohort study using data from the Veterans Affairs Corporate Data Warehouse to evaluate the relationship between iron status and mortality. We identified a pre-dialysis CKD cohort with at least one set of iron indices between 2006-2015. The cohort was divided into four iron groups based on the joint quartiles of serum transferrin saturation (percent) and ferritin concentration (ng/ml): reference (16-28%, 55-205 ng/ml), low iron (0.4-16%, 0.4-55 ng/ml), high iron (28-99.6%, 205-4941 ng/ml), and function iron deficiency (0.8-16%, 109-2783 ng/ml). We compared mortality risk between the iron groups using matching weights based on multinomial propensity score models and Poisson rate-based regression. We also evaluated if the association between iron groups and mortality differs between the diabetic and non-diabetic subgroups. Of the 80,067 eligible veterans, 32,489 were successfully matched. During the mean follow-up period of 4.0 years, adjusted relative rate (95% confidence interval) for all-cause mortality in three abnormal iron groups were increased compared to the reference: functional iron deficiency [1.21 (1.17, 1.25)], low iron [1.10 (1.07, 1.14)], and high iron [1.09 (1.06, 1.13)]. The mortality risk was similar between diabetic and non-diabetic subgroups for each iron group. Thus, an abnormal iron balance, particularly functional iron deficiency, is associated with increased mortality in CKD.

Coupled-cluster interpretation of the photoelectron spectrum of Ag3 (.).

We use the scalar relativistic ionized equation-of-motion coupled-cluster (IP-EOMCC) approaches to investigate the photoelectron spectrum of Ag3 (-), examining the effects of basis set, number of correlated electrons, level of applied theory including up to 3-hole-2-particle terms, and geometry relaxation. By employing an IP-EOMCC-based extrapolation scheme, we are able to provide an accurate interpretation and complete assignment of peaks and other key features in the experimentally observed spectra, including electron binding energies as high as about 6.5 eV.

Using Attitudes, Age and Gender to Estimate an Adolescent's Substance Use Risk.

PURPOSE: The purpose of this paper is to present a strategy for estimating an individual's risk of alcohol, cigarette and cannabis use that relies on an assessment of an adolescent's age, gender and attitude. METHODOLOGY: The authors assembled surveys from 35,987 11 through 17 year-olds assembled from 36 databases were analysed to examine the relationship between attitude and behaviour. FINDINGS: Attitudes were strongly correlated with concurrent use of alcohol, drunkenness, smoking, and cannabis, with point biserial correlations of -0.555, -0.517, -0.552 and -0.476, respectively. Logistic regression provided a means for using age, gender and attitudes to estimate an individual's risk of engaging in substance use behaviour. Developmental changes in attitudes were estimated by analysing changes in scores associated with percentile rankings for each age and gender group. Projected year-to-year changes in attitude were used as a heuristic for estimating future risk. RESEARCH LIMITATIONS: Analyses relied on cross-sectional panel data. Analyses would benefit from longitudinal data in which age-related changes in attitudes could be more precisely modelled. PRACTICAL IMPLICATIONS: Information about estimated current and future risk may use useful for motivating the adoption and implementation of effective prevention approaches by parents and care providers. ORIGINALITY: The authors present a novel method for estimating an individual's risk of substance use knowing attitude, age and gender.

Design and In Vivo Test of a Batteryless and Fully Wireless Implantable Asynchronous Pacing System.

Goal: The aim of this study is to develop a novel fully wireless and batteryless technology for cardiac pacing. METHODS: This technology uses radio frequency (RF) energy to power the implanted electrode in the heart. An implantable electrode antenna was designed for 1.2 GHz; then, it was tested in vitro and, subsequently, integrated with the rectifier and pacing circuit to make a complete electrode. The prototype implanted electrode was tested in vivo in an ovine subject, implanting it on the epicardial surface of the left ventricle. The RF energy, however, was transmitted to the implanted electrode using a horn antenna positioned 25 cm above the thorax of the sheep. RESULTS: It was demonstrated that a small implanted electrode can capture and harvest enough safe recommended RF energy to achieve pacing. Electrocardiogram signals were recorded during the experiments, which demonstrated asynchronous pacing achieved at three different rates. CONCLUSION: These results show that the proposed method has a great potential to be used for stimulating the heart and provides pacing, without requiring any leads or batteries. It hence has the advantage of potentially lasting indefinitely and may never require replacement during the life of the patient. SIGNIFICANCE: The proposed method brings forward transformational possibilities in wireless cardiac pacing, and also in powering up the implantable devices.

A far-field radio-frequency experimental exposure system with unrestrained mice.

Many studies have been performed on exploring the effects of radio-frequency (RF) energy on biological function in vivo. In particular, gene expression results have been inconclusive due, in part, to a lack of a standardized experimental procedure. This research describes a new far field RF exposure system for unrestrained murine models that reduces experimental error. The experimental procedure includes the materials used, the creation of a patch antenna, the uncertainty analysis of the equipment, characterization of the test room, experimental equipment used and setup, power density and specific absorption rate experiment, and discussion. The result of this research is an experimental exposure system to be applied to future biological studies.

Phantom pain in a patient with brachial plexus avulsion injury.

OBJECTIVE: Phantom limb pain is a painful sensation perceived in the absent limb following surgical or traumatic amputation. Phantom limb sensations, which are nonpainful, occur in nearly all amputees. Deafferentation can also produce similar symptoms. Here we report the presence of phantom pain in a deafferented limb. DESIGN: Case report. SETTING: Hospital-based outpatient clinic. PATIENT: A 65-year-old man was referred to the pain clinic for management of upper extremity pain secondary to brachial plexus avulsion (BPA) following a motor vehicle accident. Initially he noticed a feeling of growing and shrinking of his arm. Following this, the pain started gradually from his elbow extending to his fingertips covering all dermatomes. He described the pain as continuous, severe, and sharp. He also described the arm as being separate from his existing insensate arm and felt as though the fist was closed with the thumb pointing out. On physical examination, he had no sensation to fine touch or pressure below the elbow. There were no consistent areas of allodynia. He had diffuse muscle wasting in all the muscle groups of his left upper extremity, besides winging of the scapula. Electrodiagnostic studies showed a left brachial plexopathy consistent with multilevel nerve root avulsion sparing the dorsal rami. CONCLUSION: This is a report of phantom limb sensations and phantom pain following BPA in an intact but flaccid and insensate limb.

Communication: Coupled-cluster interpretation of the photoelectron spectrum of Au3⁻.

We use the scalar relativistic ionized equation-of-motion coupled-cluster approaches, correlating valence and semi-core electrons and including up to 3-hole-2-particle terms in the ionizing operator, to investigate the photoelectron spectrum of Au3⁻. We provide an accurate assignment of peaks and shoulders in the experimental photoelectron spectrum of Au3⁻ for the first time.

Communication: Determining the lowest-energy isomer of Au8: 2D, or not 2D.

A parallel numerical derivative code, combined with parallel implementation of the coupled-cluster method with singles, doubles, and non-iterative triples (CCSD(T)), is used to optimize the geometries of the low-energy structures of the Au8 particle. The effects of geometry relaxation at the CCSD(T) level and the combined effects of the basis set and core-valence correlations are examined and the results are compared with the corresponding second-order Møller-Plesset perturbation theory calculations. The highest-level computations, in which the single-point CCSD(T) calculations employing the correlation-consistent basis set of the cc-pVTZ quality and the associated relativistic effective core potential (ECP), both optimized for gold, and correlating the 5d(10)6s(1) valence and 5s(2)5p(6) semi-core electrons, are combined with the geometrical information obtained with the corresponding CCSD(T)/cc-pVDZ/ECP approach, favor the planar configuration, with the next three non-planar structures separated by 4-6 kcal/mol. In agreement with the earlier work, smaller-basis set CCSD(T) computations provide unreliable results for the relative energetics, even when the geometries are optimized at the CCSD(T) level.

Aerobic oxidation of methanol to formic acid on Au8-: benchmark analysis based on completely renormalized coupled-cluster and density functional theory calculations.

The left-eigenstate completely renormalized coupled-cluster (CC) method with singles, doubles, and noniterative triples [CR-CC(2,3)] and a few representative density functional theory (DFT) approaches have been applied to methanol oxidation to formic acid on a Au8(-) cluster, which is a model for aerobic oxidations on gold nanoparticles. It is demonstrated that CR-CC(2,3) supports the previous exothermic reaction mechanism, placing the initial rate-determining transition state, which corresponds to hydrogen transfer from the methoxy species to the molecular oxygen, at about 20 kcal/mol above the reactants, less than 40 kcal/mol above the O2 and CH3O(-) species coadsorbed on Au8(-), and considerably above the remaining two transition states along the reaction pathway. The DFT calculations using the previously exploited M06 hybrid functional show reasonable agreement with CR-CC(2,3), but B3LYP offers additional improvements in the description of the relevant activation energies. Pure functionals, including M06-L, BP86, and TPSS, do not work well, significantly underestimating the activation barriers, but dispersion corrections, as in B97-D, bring the results closer to the M06 accuracy level.