Patient-Level Characteristics Associated with Tobacco Users and Nonusers at a Student-Run Free Clinic.

OBJECTIVES: Many tobacco users are motivated to quit but lack the resources to do so. To date, studies characterizing tobacco users at student-run free clinics have used small sample sizes, which may not be large enough to detect differences across key variables. As such, we assessed sociodemographic differences between tobacco users and nonusers at a student-run free clinic using a pooled cross-sectional design. METHODS: We used patient-level data from the electronic health records for all of the patients who were seen during January 2012 to February 2020 inclusive. Our dependent variable was whether patients self-reported tobacco use. We assessed for differences across age, sex, race/ethnicity, and education level using a multivariable logistic regression model. RESULTS: Across 4264 patients, 28.7% reported tobacco use. When controlling for other factors, greater odds of tobacco use were observed in this cohort for patients who were male (odds ratio [OR] 1.690, 95% confidence interval [CI] 1.468-1.944), those with educational attainment of 9th to 11th grade (OR 2.291, 95% CI 1.558-3.369), and those who were high school graduates/completed the General Education Development test (OR 1.849, 95% CI 1.295-2.638) compared with those with less than a high school education. Similarly, patients of older age had greater odds of tobacco use. CONCLUSIONS: Our study found patient-level differences that may need to be integrated into improving the reach of intervention methods. Future research should look at a broader set of metrics (eg, geographic location, socioeconomic status) and ascertain reasons for sociodemographic differences observed.

Predictors of intent to utilize the emergency department among a free clinic's patients.

OBJECTIVE: Primary care use helps reduce utilization of more expensive modes of care, such as the emergency department (ED). Although most studies have investigated this association among patients with insurance, few have done so for patients without insurance. We used data from a free clinic network to assess the association between free clinic use and intent to use the ED. METHODS: Data were collected from a free clinic network's electronic health records on adult patients from January 2015 to February 2020. Our outcome was whether patients reported themselves as 'very likely' to visit the ED if the free clinics were unavailable. The independent variable was frequency of free clinic use. Using a multivariable logistic regression model, we controlled for other factors, such as patient demographic factors, social determinants of health, health status, and year effect. RESULTS: Our sample included 5008 visits. When controlling for other factors, higher odds of expressing ED interest were observed for patients who are non-Hispanic Black, older, not married, lived with others, had lower education, were homeless, had personal transportation, lived in rural areas, and had a higher comorbidity burden. In sensitivity analyses, higher odds were observed for dental, gastrointestinal, genitourinary, musculoskeletal, or respiratory conditions. CONCLUSIONS: In the free clinic space, several patient demographic, social determinants of health and medical conditions were independently associated with greater odds of reporting intent on visiting the ED. Additional interventions that improve access and use of free clinics (e.g., dental) may keep patients without insurance from the ED.

Sub 20 cm-1 computational prediction of the CH bond energy - a case of systematic error in computational thermochemistry.

The bond dissociation energy of methylidyne, D0(CH), is studied using an improved version of the High-Accuracy Extrapolated ab initio Thermochemistry (HEAT) approach as well as the Feller-Peterson-Dixon (FPD) model chemistry. These calculations, which include basis sets up to nonuple (aug-cc-pCV9Z) quality, are expected to be capable of providing results substantially more accurate than the ca. 1 kJ mol-1 level that is characteristic of standard high-accuracy protocols for computational thermochemistry. The calculated 0 K CH bond energy (27 954 ± 15 cm-1 for HEAT and 27 956 ± 15 cm-1 for FPD), along with equivalent treatments of the CH ionization energy and the CH+ dissociation energy (85 829 ± 15 cm-1 and 32 946 ± 15 cm-1, respectively), were compared to the existing benchmarks from Active Thermochemical Tables (ATcT), uncovering an unexpected difference for D0(CH). This has prompted a detailed reexamination of the provenance of the corresponding ATcT benchmark, allowing the discovery and subsequent correction of a systematic error present in several published high-level calculations, ultimately yielding an amended ATcT benchmark for D0(CH). Finally, the current theoretical results were added to the ATcT Thermochemical Network, producing refined ATcT estimates of 27 957.3 ± 6.0 cm-1 for D0(CH), 32 946.7 ± 0.6 cm-1 for D0(CH+), and 85 831.0 ± 6.0 cm-1 for IE(CH).

Atomic isotropic hyperfine properties for second row elements (Al-Cl).

Isotropic hyperfine properties have been obtained for the second row elements Al-Cl using a systematic composite approach consisting of a sequence of core/valence correlation consistent basis sets, up through aug-cc-pCV7Z, along with configuration interaction and coupled cluster methods. The best nonrelativistic final values for the atomic ground states (in MHz) are -1.80 27Al (2Po 1/2), -24.31 29Si (3P0), 63.70 31P (4So 3/2), 20.77 33S (3P2), and 35.42 35Cl (2Po 3/2). We find a large K shell contribution to the spin density at the nucleus that is almost canceled by the L and M shell contributions. The spin density in atomic units is approximately linear with respect to the atomic number.

Antibiotic prescribing patterns for acute respiratory infections in a free clinic network: A pooled cross-sectional study.

In the United States, overprescribing of antibiotics for viral respiratory infections and antimicrobial resistance continue to be public health concerns. To date, no literature has focused on antibiotic prescribing patterns from free clinics. To address this gap, we used patient-level data from a student-run free clinic network of four primary care clinics to assess factors associated with inappropriate antibiotic prescribing for viral respiratory infections. Treatment plans were deemed inappropriate if any type of antibiotic was prescribed. We used unpaired t-tests and chi-square tests to assess for differences in receiving an inappropriate antibiotic prescription by patient-level factors (i.e., age, race/ethnicity, sex, educational attainment, preferred language, insurance status). Of 298 visits, 22.5% did not meet treatment guidelines. No patient-level factors studied were associated with inappropriate antibiotic prescribing. Our findings suggest other factors, beyond patient-level, may be drivers of variation in antibiotic prescribing in free clinics.

Atomic isotropic hyperfine properties for first row elements (B-F) revisited.

Benchmark quality isotropic hyperfine properties have been obtained for first row elements (B-F) using a systematic composite approach consisting of a sequence of core/valence correlation consistent basis sets, up through aug-cc-pCV8Z, along with configuration interaction and coupled cluster theory methods. The best nonrelativistic final values (in MHz) are 10.64 (B), 20.22 (C), 10.59 (N), -31.74 (O), and 318.30 (F) and are in very good agreement with available experimental values for these difficult-to-describe properties. Agreement is especially close in the case of N, which has the most accurate experimental value. The spin densities derived from the best composite level of theory were found to closely follow a simple quadratic scaling with the atomic number, Z. Observed convergence rates in the 1-particle and n-particle expansions obtained here may be useful in judging likely accuracy that can be expected in studies of molecular systems.

Elaborated thermochemical treatment of HF, CO, N2, and H2O: Insight into HEAT and its extensions.

Empirical, highly accurate non-relativistic electronic total atomization energies (eTAEs) are established by combining experimental or computationally converged treatments of the nuclear motion and relativistic contributions with the total atomization energies of HF, CO, N2, and H2O obtained from the Active Thermochemical Tables. These eTAEs, which have estimated (2σ) uncertainties of less than 10 cm-1 (0.12 kJ mol-1), form the basis for an analysis of high-level ab initio quantum chemical calculations that aim at reproducing these eTAEs for the title molecules. The results are then employed to analyze the performance of the high-accuracy extrapolated ab initio thermochemistry, or High-Accuracy Extrapolated Ab Initio Thermochemistry (HEAT), family of theoretical methods. The method known as HEAT-345(Q), in particular, is found to benefit from fortuitous error cancellation between its treatment of the zero-point energy, extrapolation errors in the Hartree-Fock and coupled cluster contributions, neglect of post-(T) core-correlation, and the basis-set error involved in higher-level correlation corrections. In addition to shedding light on a longstanding curiosity of the HEAT protocol-where the cheapest HEAT-345(Q) performs comparably to the theoretically more complete HEAT-456QP procedure-this study lays the foundation for extended HEAT variants that offer substantial improvements in accuracy relative to the established approaches.

Comparison of Factors Identified by Patients and Physicians Associated with Hospital Readmission (COMPARE2).

OBJECTIVE: Factors contributing to hospital readmission have rarely been sought from the patient perspective. Furthermore, it is unclear how patients and physicians compare in identifying factors contributing to readmission. The objective of the study was to identify and compare factors contributing to hospital readmission identified by patients and physicians by surveying participants upon hospital readmission to a teaching medicine service. METHODS: Patients 18 years and older who were discharged and readmitted to the same service within 30 days and the physicians caring for these patients were surveyed to identify factors contributing to readmission. Secondary outcomes included comparing responses between groups and determining level of agreement. Patients could be surveyed multiple times on subsequent readmissions; physicians could be surveyed for multiple patients. RESULTS: A total of 131 patients and 37 physicians were consented. The mean patient age was 60.1 years (standard deviation 16.8 years) and 55.6% were female; 56.4% were white, and 42.1% were black/African American. In total, 179 patient surveys identified "multiple medical problems" (48.6%), "trouble completing daily activities" (45.8%), and "discharged too soon" (43.6%) most frequently as contributing factors; 231 physician surveys identified "multiple medical problems" (45.0%) and "medical condition too difficult to care for at home" (35.6%) most frequently as contributing factors. Paired survey results were available for 135 readmissions and showed fair agreement for only 1 factor but no agreement for 5 factors. CONCLUSIONS: Patients identified previously unknown factors contributing to readmission. Little agreement existed between patients and physicians. Additional research is needed to determine how best to address patient-identified factors contributing to readmission.

Enthalpy of Formation of C2H2O4 (Oxalic Acid) from High-Level Calculations and the Active Thermochemical Tables Approach.

High-level coupled cluster calculations obtained with the Feller-Peterson-Dixon (FPD) approach and new data from the most recent version of the Active Thermochemical Tables (ATcT) are used to reassess the enthalpy of formation of gas-phase C2H2O4 (oxalic acid). The theoretical value was further calibrated by comparing FPD and ATcT gas-phase enthalpies of formation for H2CO (formaldehyde) and the two low-lying conformations of C2H4O2 ( syn and anti acetic acid). The FPD approach produces a theoretical enthalpy of formation of gas-phase oxalic acid of -732.2 ± 4.0 kJ/mol at 298.15 K (-721.8 ± 4.0 kJ/mol at 0 K). An independently obtained ATcT value, based on reassessing the existent experimental determinations and expanding the resulting thermochemical network with select mid-level composite theoretical results, disagrees with several earlier recommendations that were based solely on experimental determinations but is in excellent accord with the current FPD value. The inclusion of the latter in the most recent ATcT thermochemical network produces a further refined value for the gas-phase enthalpy of formation, -731.6 ± 1.2 kJ/mol at 298.15 K (-721.0 ± 1.2 kJ/mol at 0 K). The condensed-phase ATcT enthalpy of formation of oxalic acid is -829.7 ± 0.5 kJ/mol, and the resulting sublimation enthalpy is 98.1 ± 1.3 kJ/mol, both at 298.15 K.

A theoretical study of the adiabatic and vertical ionization potentials of water.

Theoretical predictions of the three lowest adiabatic and vertical ionization potentials of water were obtained from the Feller-Peterson-Dixon approach. This approach combines multiple levels of coupled cluster theory with basis sets as large as aug-cc-pV8Z in some cases and various corrections up to and including full configuration interaction theory. While agreement with experiment for the adiabatic ionization potential of the lowest energy 2B1 state was excellent, differences for other states were much larger, sometimes exceeding 10 kcal/mol (0.43 eV). Errors of this magnitude are inconsistent with previous benchmark work on 52 adiabatic ionization potentials, where a root mean square of 0.20 kcal/mol (0.009 eV) was found. Difficulties in direct comparisons between theory and experiment for vertical ionization potentials are discussed. With regard to the differences found for the 2A1/2Πu and 2B2 adiabatic ionization potentials, a reinterpretation of the experimental spectrum appears justified.

Density Functional Theory and the Basis Set Truncation Problem with Correlation Consistent Basis Sets: Elephant in the Room or Mouse in the Closet?

Two recent papers in this journal called into question the suitability of the correlation consistent basis sets for density functional theory (DFT) calculations, because the sets were designed for correlated methods such as configuration interaction, perturbation theory, and coupled cluster theory. These papers focused on the ability of the correlation consistent and other basis sets to reproduce total energies, atomization energies, and dipole moments obtained from "quasi-exact" multiwavelet results. Undesirably large errors were observed for the correlation consistent basis sets. One of the papers argued that basis sets specifically optimized for DFT methods were "essential" for obtaining high accuracy. In this work we re-examined the performance of the correlation consistent basis sets by resolving problems with the previous calculations and by making more appropriate basis set choices for the alkali and alkaline-earth metals and second-row elements. When this is done, the statistical errors with respect to the benchmark values and with respect to DFT optimized basis sets are greatly reduced, especially in light of the relatively large intrinsic error of the underlying DFT method. When judged with respect to high-quality Feller-Peterson-Dixon coupled cluster theory atomization energies, the PBE0 DFT method used in the previous studies exhibits a mean absolute deviation more than a factor of 50 larger than the quintuple zeta basis set truncation error.

Neuroleptic Malignant Syndrome: Diagnosis and Management.

OBJECTIVE: To provide an overview of neuroleptic malignant syndrome (NMS) for the general practitioner with the most up-to-date information on etiology, workup, and management. DATA SOURCES: The search using PubMed included articles with the key words neuroleptic malignant syndrome, antipsychotics, neuroleptics, diagnosis, and treatment of neuroleptic malignant syndrome published in English from January 2000 to 2017. Single-case reports and articles dealing with the pediatric patient population were excluded. STUDY SELECTION: Over 4,000 articles met the search criteria. After eliminating single-case reports, pediatric cases, reports in pregnant patients, and duplicates, 87 articles underwent screening. Forty-two articles were included in this review. RESULTS: The literature is rich with cases of NMS associated with the use of neuroleptics and various medications with neuroleptic-like effects. Questions remain with regard to pathophysiology and optimal treatment. NMS is a rare but potentially lethal consequence of the use of antipsychotic medications that requires familiarity with the condition in order to rapidly recognize its onset and appropriately intervene. CONCLUSIONS: NMS mortality rates have declined over the past 30 years, most likely due to early recognition of the syndrome and appropriate intervention. Nonetheless, clinicians, especially primary care clinicians who are using this class of drugs more often for adjunctive treatments, must be cognizant of this syndrome and the implications of their use.​.

Estimating the intrinsic limit of the Feller-Peterson-Dixon composite approach when applied to adiabatic ionization potentials in atoms and small molecules.

Benchmark adiabatic ionization potentials were obtained with the Feller-Peterson-Dixon (FPD) theoretical method for a collection of 48 atoms and small molecules. In previous studies, the FPD method demonstrated an ability to predict atomization energies (heats of formation) and electron affinities well within a 95% confidence level of ±1 kcal/mol. Large 1-particle expansions involving correlation consistent basis sets (up to aug-cc-pV8Z in many cases and aug-cc-pV9Z for some atoms) were chosen for the valence CCSD(T) starting point calculations. Despite their cost, these large basis sets were chosen in order to help minimize the residual basis set truncation error and reduce dependence on approximate basis set limit extrapolation formulas. The complementary n-particle expansion included higher order CCSDT, CCSDTQ, or CCSDTQ5 (coupled cluster theory with iterative triple, quadruple, and quintuple excitations) corrections. For all of the chemical systems examined here, it was also possible to either perform explicit full configuration interaction (CI) calculations or to otherwise estimate the full CI limit. Additionally, corrections associated with core/valence correlation, scalar relativity, anharmonic zero point vibrational energies, non-adiabatic effects, and other minor factors were considered. The root mean square deviation with respect to experiment for the ionization potentials was 0.21 kcal/mol (0.009 eV). The corresponding level of agreement for molecular enthalpies of formation was 0.37 kcal/mol and for electron affinities 0.20 kcal/mol. Similar good agreement with experiment was found in the case of molecular structures and harmonic frequencies. Overall, the combination of energetic, structural, and vibrational data (655 comparisons) reflects the consistent ability of the FPD method to achieve close agreement with experiment for small molecules using the level of theory applied in this study.

Enthalpy of Formation of N2H4 (Hydrazine) Revisited.

In order to address the accuracy of the long-standing experimental enthalpy of formation of gas-phase hydrazine, fully confirmed in earlier versions of Active Thermochemical Tables (ATcT), the provenance of that value is re-examined in light of new high-end calculations of the Feller-Peterson-Dixon (FPD) variety. An overly optimistic determination of the vaporization enthalpy of hydrazine, which created an unrealistically strong connection between the gas phase thermochemistry and the calorimetric results defining the thermochemistry of liquid hydrazine, was identified as the probable culprit. The new enthalpy of formation of gas-phase hydrazine, based on balancing all available knowledge, was determined to be 111.57 ± 0.47 kJ/mol at 0 K (97.42 ± 0.47 kJ/mol at 298.15 K). Close agreement was found between the ATcT (even excluding the latest theoretical result) and the FPD enthalpy.

Application of a convergent, composite coupled cluster approach to bound state, adiabatic electron affinities in atoms and small molecules.

Benchmark quality adiabatic electron affinities for a collection of atoms and small molecules were obtained with the Feller-Peterson-Dixon composite coupled cluster theory method. Prior applications of this method demonstrated its ability to accurately predict atomization energies/heats of formation for more than 170 molecules. In the current work, the 1-particle expansion involved very large correlation consistent basis sets, ranging up to aug-cc-pV9Z (aug-cc-pV10Z for H and H2), with the goal of minimizing the residual basis set truncation error that must otherwise be approximated with extrapolation formulas. The n-particle expansion begins with coupled cluster calculations through iterative single and double excitations plus a quasiperturbative treatment of "connected" triple excitations (CCSD(T)) pushed to the complete basis set limit followed by CCSDT, CCSDTQ, or CCSDTQ5 corrections. Due to the small size of the systems examined here, it was possible in many cases to extend the n-particle expansion to the full configuration interaction wave function limit. Additional, smaller corrections associated with core/valence correlation, scalar relativity, anharmonic zero point vibrational energies, and non-adiabatic effects were also included. The overall root mean square (RMS) deviation was 0.005 eV (0.12 kcal/mol). This level of agreement was comparable to what was found with molecular heats of formation. A 95% confidence level corresponds to roughly twice the RMS value or 0.01 eV. While the atomic electron affinities are known experimentally to high accuracy, the molecular values are less certain. This contributes to the difficulty of gauging the accuracy of the theoretical results. A limited number of electron affinities were determined with the explicitly correlated CCSD(T)-F12b method. After extending the VnZ-F12 orbital basis sets with additional diffuse functions, the F12b method was found to accurately reproduce the best F/F(-) value obtained with standard methods, but it underestimated the CH3/CH3 (-) value by 0.01 eV.

Statistical Electronic Structure Calibration Study of the CCSD(T*)-F12b Method for Atomization Energies.

In the explicitly correlated CCSD(T)-F12b coupled cluster method only the singles and doubles component of the energy benefits from inclusion of terms involving the interelectronic distance. Consequently, only that component exhibits accelerated convergence with respect to the 1-particle basis set. The smaller perturbative triples component converges at the same rate as the corresponding piece in standard CCSD(T). With the alternative CCSD(T*)-F12b method the triples correlation energy is scaled up by the ratio of explicitly correlated to standard second-order perturbation theory correlation energies in an attempt to better approximate the basis set limit. An extensive and diverse 212 molecule collection of reference total atomization energies, developed with large basis sets (up to aug-cc-pV9Z in some cases) and standard CCSD(T), was used to calibrate the performance of CCSD(T*). Scaling of the (T) energy led to improved results relative to raw F12b values but only provided a statistical advantage over previously proposed complete basis set extrapolation techniques for the smallest basis sets. With larger sets, scaling (T) produced noticeably poorer results, sometimes by a factor of 2. In agreement with earlier studies, basis set extrapolated CCSD(T)-F12b was found to exhibit a systematic bias toward overestimating reference atomization energies with an error that increases with the magnitude of the valence correlation energy.

A systematic approach to vertically excited states of ethylene using configuration interaction and coupled cluster techniques.

A systematic sequence of configuration interaction and coupled cluster calculations were used to describe selected low-lying singlet and triplet vertically excited states of ethylene with the goal of approaching the all electron, full configuration interaction/complete basis set limit. Included among these is the notoriously difficult, mixed valence/Rydberg (1)B(1u) V state. Techniques included complete active space and iterative natural orbital configuration interaction with large reference spaces which led to variational spaces of 1.8 × 10(9) parameters. Care was taken to avoid unintentionally biasing the results due to the widely recognized sensitivity of the V state to the details of the calculation. The lowest vertical and adiabatic ionization potentials to the (2)B(3u) and (2)B3 states were also determined. In addition, the heat of formation of twisted ethylene (3)A1 was obtained from large basis set coupled cluster theory calculations including corrections for core/valence, scalar relativistic and higher order correlation recovery.

An expanded calibration study of the explicitly correlated CCSD(T)-F12b method using large basis set standard CCSD(T) atomization energies.

The effectiveness of the recently developed, explicitly correlated coupled cluster method CCSD(T)-F12b is examined in terms of its ability to reproduce atomization energies derived from complete basis set extrapolations of standard CCSD(T). Most of the standard method findings were obtained with aug-cc-pV7Z or aug-cc-pV8Z basis sets. For a few homonuclear diatomic molecules it was possible to push the basis set to the aug-cc-pV9Z level. F12b calculations were performed with the cc-pVnZ-F12 (n = D, T, Q) basis set sequence and were also extrapolated to the basis set limit using a Schwenke-style, parameterized formula. A systematic bias was observed in the F12b method with the (VTZ-F12/VQZ-F12) basis set combination. This bias resulted in the underestimation of reference values associated with small molecules (valence correlation energies <0.5 E(h)) and an even larger overestimation of atomization energies for bigger systems. Consequently, caution should be exercised in the use of F12b for high accuracy studies. Root mean square and mean absolute deviation error metrics for this basis set combination were comparable to complete basis set values obtained with standard CCSD(T) and the aug-cc-pVDZ through aug-cc-pVQZ basis set sequence. However, the mean signed deviation was an order of magnitude larger. Problems partially due to basis set superposition error were identified with second row compounds which resulted in a weak performance for the smaller VDZ-F12/VTZ-F12 combination of basis sets.

Benchmarks of improved complete basis set extrapolation schemes designed for standard CCSD(T) atomization energies.

Simple modifications of complete basis set extrapolation formulas chosen from the literature are examined with respect to their abilities to reproduce a diverse set of 183 reference atomization energies derived primarily from very large basis set standard, frozen core coupled-cluster singles, doubles plus perturbative triples (CCSD(T)) with the aug-cc-pVnZ basis sets. This reference set was augmented with a few larger chemical systems treated with explicitly correlated CCSD(T)-F12b using a quadruple zeta quality basis set followed by extrapolation to complete basis set limit. Tuning the extrapolation formula parameters for the present reference set resulted in substantial reductions in the error metrics. In the case of the best performing approach, the aVnZ extrapolated results are equivalent to or better than results obtained from raw aV(n + 3)Z basis set calculations. To the extent this behavior holds for molecules outside the reference set, it represents an improvement of at least one basis set level over the original formulations and a further significant reduction in the amount of computer time needed to accurately approximate the basis set limit.

Anharmonic zero point vibrational energies: tipping the scales in accurate thermochemistry calculations?

Anharmonic zero point vibrational energies (ZPVEs) calculated using both conventional CCSD(T) and MP2 in combination with vibrational second-order perturbation theory (VPT2) are compared to explicitly correlated CCSD(T)-F12 and MP2-F12 results that utilize vibrational configuration interaction (VCI) theory for 26 molecules of varying size. Sequences of correlation consistent basis sets are used throughout. It is found that the explicitly correlated methods yield results close to the basis set limit even with double-zeta quality basis sets. In particular, the anharmonic contributions to the ZPVE are accurately recovered at just the MP2 (or MP2-F12) level of theory. Somewhat surprisingly, the best vibrational CI results agreed with the VPT2 values with a mean unsigned deviation of just 0.09 kJ/mol and a standard deviation of just 0.11 kJ/mol. The largest difference was observed for C(4)H(4)O (0.34 kJ/mol). A simplified version of the vibrational CI procedure that limited the modal expansion to at most 2-mode coupling yielded anharmonic corrections generally within about 0.1 kJ/mol of the full 3- or 4-mode results, except in the cases of C(3)H(8) and C(4)H(4)O where the contributions were underestimated by 1.3 and 0.8 kJ/mol, respectively (34% and 40%, respectively). For the molecules considered in this work, accurate anharmonic ZPVEs are most economically obtained by combining CCSD(T)-F12a/cc-pVDZ-F12 harmonic frequencies with either MP2/aug-cc-pVTZ/VPT2 or MP2-F12/cc-pVDZ-F12/VCI anharmonic corrections.