Integrative transcriptomics and proteomics analysis reveal the protection of Astragaloside IV against myocardial fibrosis by regulating senescence.

Myocardial fibrosis (MF) is a pivotal pathological process implicated in various cardiovascular diseases, particularly heart failure. Astragaloside IV (AS-IV), a natural compound derived from Astragalus membranaceus, possesses potent cardioprotective properties. However, the precise molecular mechanisms underlying its anti-MF effects, particularly in relation to senescence, remain elusive. Thus, this study aimed to investigate the therapeutic potential and underlying molecular mechanisms of AS-IV in treating ISO-induced MF in mice, employing transcriptomics, proteomics, in vitro, and in vivo experiments. We assessed the positive effects of AS-IV on ISO-induced MF using HE staining, Masson staining, ELISA, immunohistochemical staining, transthoracic echocardiography, transmission electron microscopy, and DHE fluorescence staining. Additionally, we elucidated the regulatory role of AS-IV in MF through comprehensive transcriptomics and proteomics analyses, complemented by Western blotting and RT-qPCR validation of pertinent molecular pathways. Our findings demonstrated that AS-IV treatment markedly attenuated ISO-induced myocardial injury and oxidative stress, concomitantly inhibiting the release of SASPs. Furthermore, integrated transcriptomics and proteomics analyses revealed that the anti-MF mechanism of AS-IV was associated with regulating cellular senescence and the p53 signaling pathway. These results highlight AS-IV exerts its anti-MF effects not only by inhibiting oxidative stress but also by modulating senescence through the p53 signaling pathway.

Integration of network pharmacology and serum medicinal chemistry to investigate the pharmacological mechanisms of QiZhuYangGan Decoction in the treatment of hepatic fibrosis.

ETHNOPHARMACOLOGICAL RELEVANCE: Qizhuyanggan Decoction (QZD), a traditional Chinese medicine formula, is frequently utilized in clinical practice for managing hepatic fibrosis. However, the specific target and mechanism of action of QZD for hepatic fibrosis treatment remain unknown. AIM OF THE STUDY: By combining network pharmacology, serum medicinal chemistry, and experimental validation methods, our study aimed to investigate the therapeutic effects of QZD on hepatic fibrosis, the anti-hepatic fibrosis active ingredients, and the possible mechanism of anti-hepatic fibrosis action. MATERIALS AND METHODS: The study aimed to investigate the therapeutic effect of QZD on hepatic fibrosis induced by CCl4 in SD rats, as well as its mechanism of action. The rats were anesthetized intraperitoneally using 3% pentobarbital and were executed after asphyxiation with high concentrations of carbon dioxide. Several techniques were employed to evaluate the efficacy of QZD, including ELISA, Western blot, HYP reagent assay, and various pathological examinations such as HE, Masson, Sirius Red staining, and immunohistochemistry (IHC). Additionally, serum biochemical assays were conducted to assess the effect of QZD on liver injury. Network pharmacology, UPLC, molecular docking, and molecular dynamics simulation were utilized to explore the mechanism of QZD in treating hepatic fibrosis. Finally, experimental validation was performed through ELISA, IHC, RT-qPCR, and Western blot analysis. RESULT: Liver histopathology showed that QZD reduced inflammation and inhibited collagen production, and QZD significantly reduced HA and LN content to treat hepatic fibrosis. Serum biochemical analysis showed that QZD improved liver injury. Network pharmacology combined with UPLC screened six active ingredients and obtained 87 targets for the intersection of active ingredients and diseases. The enrichment analysis results indicated that the PI3K/AKT pathway might be the mechanism of action of QZD in the treatment of hepatic fibrosis, and counteracting the inflammatory response might be one of the pathways of action of QZD. Molecular docking and molecular dynamics simulations showed that the active ingredient had good binding properties with PI3K, AKT, and mTOR proteins. Western blot, ELISA, PCR, and IHC results indicated that QZD may treat hepatic fibrosis by inhibiting the PI3K/AKT/mTOR pathway and suppressing M1 macrophage polarization, while also promoting M2 macrophage polarization. CONCLUSIONS: QZD may be effective in the treatment of hepatic fibrosis by inhibiting the PI3K/AKT/mTOR signaling pathway and M1 macrophage polarization, while promoting M2 macrophage polarization. This provides a strong basis for the clinical application of QZD.

Effect of pueraria on left ventricular remodelling in HFrEF: A systematic review and meta-analysis.

BACKGROUND: Heart failure with reduced ejection fraction (HFrEF) is a prevalent cardiovascular disease globally, posing a significant burden on healthcare and society. Left ventricular remodelling is the primary pathology responsible for HFrEF development and progression, leading to increased morbidity and mortality. Pueraria, a traditional Chinese herbal medicine and food, is commonly used in China to treat HFrEF. Accumulating evidence suggests that pueraria can effectively reverse left ventricular remodelling in HFrEF patients. This meta-analysis aims to assess the impact of pueraria on left ventricular remodelling in HFrEF patients. METHODS: Eight electronic databases, including PubMed, EMBASE, Clinicaltrials.gov, Cochrane Library, Wanfang, CNKI, CQVIP, and CBM were searched for literature from inception to June 2023. All randomized controlled trials (RCTs) using pueraria in the treatment of HFrEF were included. The Cochrane Risk of Bias tool was utilized for RCTs' methodological evaluation, while Review Manager 5.4.1 was used to analyze the data. RESULTS: Nineteen RCTs with a total of 1,911 patients (1,077 males and 834 females) were identified. Meta-analysis indicated that combination medication of pueraria and conventional medicine (CM) was superior to the CM alone in raising left ventricular ejection fraction (LVEF; MD = 6.46, 95% CI, 4.88 to 8.04, P < 0.00001), and decreasing left ventricular end-diastolic diameter (LVEDD; MD = -4.78, 95% CI, -6.55 to -3.01, P < 0.00001), left ventricular end-Systolic diameter (LVESD; MD = -3.98, 95% CI, -5.98 to -1.99, P < 0.00001) and N-terminal pro-brain natriuretic peptide (NT-proBNP; MD = -126.16, 95% CI, -185.30 to -67.03, P < 0.0001). Besides, combination medication improved clinical efficacy rate (RR = 3.42, 95% CI, 2.54 to 4.59, P < 0.00001), 6-min walk test (6-MWT; MD = 65.54, 95% CI, 41.77 to 89.31, P < 0.00001), and TCM syndrome score efficacy (RR = 3.03, 95% CI, 1.57 to 5.83, P = 0.0009). Regarding safety, no difference was observed for adverse events (RR = 0.59, 95% CI, 0.22 to 1.54, P = 0.28). CONCLUSION: The use of pueraria combined with conventional medicine in HFrEF patients has superiority over conventional medicine alone in ameliorating cardiac function and reversing left ventricular remodeling. Moreover, combination medication has no increase in adverse drug events. Given some limitations, more prudence and high-quality clinical trials are needed in the future to verify the conclusions.

Epirubicin and gait apraxia: a real-world data analysis of the FDA Adverse Event Reporting System database.

Introduction: Epirubicin is widely used in many malignancies with good efficacy and tolerability. However, investigations about adverse events (AEs) using real-world information are still insufficient. Methods: We extracted Epirubicin-related reports submitted between the first quarter of 2014 and first quarter of 2023 from FAERS database. Four algorithms were utilized to evaluate whether there was a significant correlation between Epirubicin and AEs. Results: After de-duplicating, a total of 3919 cases were extracted. Among the 3919 cases, we identified 1472 AEs, 253 of which were found to be adverse drug reactions (ADRs) associated with Epirubicin. We analysed the occurrence of Epirubicin-induced ADRs and found several unexpected significant ADRs, such as hepatic artery stenosis, hepatic artery occlusion, intestinal atresia and so on. Interestingly, we found gait apraxia, a neurological condition, was also significantly associated with Epirubicin. To our knowledge, there haven't studies that have reported an association between gait disorders and the usage of epirubicin. Discussion: Our study identified new unexpected significant ADRs related to Epirubicin, providing new perspectives to the clinical use of Epirubicin.

Qige Huxin Formula Attenuates Isoprenaline-Induced Cardiac Fibrosis in Mice via Modulating Gut Microbiota and Protecting Intestinal Integrity.

Background: The composition and metabolic activities of gut microbiota are strongly interconnected with cardiac fibrosis (CF) and heart failure (HF). Qige Huxin formula (QHF), a traditional Chinese medicine (TCM) formulation originating from a classical Fangji Huangqi decoction, has been widely used to clinically treat HF for decades. However, it is still unclear whether QHF alleviates CF by modulating gut microbiota and intestinal integrity. Purpose: This study aimed to investigate the cardioprotective effects of QHF in isoprenaline-induced CF through modulating gut microbiota and intestinal integrity. Methods: Fifty mice were randomly divided into five groups after one week of acclimatization feeding: control group, model group, 2.56 g/kg/d group (low-dose QHF), 5.12 g/kg/d group (high-dose QHF), and meto group (15 mg/kg/d). The CF model was established by subcutaneously injecting the mice with isoprenaline (10 mg/kg/d for 14 days), followed by QHF treatment. The heart volume, cardiac weight index (CWI), serum myocardial enzymes, serum inflammatory cytokines, serum lipopolysaccharide, histopathology of the heart and colon tissues, ZO-1, and occludin of colon tissues were then measured. Fecal samples from mice were analyzed using 16S rRNA sequencing. Results: QHF treatment significantly reduced heart volume, CWI, and serum CK and CK-MB levels, attenuated cardiac histopathological alterations, and alleviated CF. QHF treatment also downregulated TNF-α, IL-1ß, and IL-6 in serum. Moreover, QHF treatment decreased the serum level of lipopolysaccharide and maintained intestinal integrity by upregulating ZO-1 and occludin. The 16S rRNA microbiota analysis revealed that QHF treatment increased the relative abundance of Marvinbryantia and Phascolarctobacterium. Conclusions: QHF treatment exerts cardioprotective effects through modulating gut microbiota, protecting intestinal integrity, and alleviating inflammation. This study shows that gut microbiota may enhance heart-gut interaction.

Astragaloside IV Ameliorates Isoprenaline-Induced Cardiac Fibrosis in Mice via Modulating Gut Microbiota and Fecal Metabolites.

Aim: Gut microbiota is of crucial importance to cardiac health. Astragaloside IV (AS-IV) is a main active ingredient of Huangqi, a traditional edible and medicinal herb that has been shown to have beneficial effects on cardiac fibrosis (CF). However, it is still uncertain whether the consumption of AS-IV alleviates cardiac fibrosis through the gut microbiota and its metabolites. Therefore, we assessed whether the anti-fibrosis effect of AS-IV is associated with changes in intestinal microbiota and fecal metabolites and if so, whether some specific gut microbes are conducive to the benefits of AS-IV. Methods: Male C57BL-6J mice were subcutaneously injected with isoprenaline (ISO) to induce cardiac fibrosis. AS-IV was administered to mice by gavage for 14 days. The effects of AS-IV on cardiac function, myocardial enzyme, cardiac weight index (CWI), and histopathology of ISO-induced CF mice were investigated. Moreover, 16S rRNA sequencing was used to establish gut-microbiota profiles. Fecal-metabolites profiles were established using the liquid chromatograph-mass spectrometry (LC-MS). Results: AS-IV treatment prevented cardiac dysfunction, ameliorated myocardial damage, histopathological changes, and cardiac fibrosis induced by ISO. AS-IV consumption increased the richness of Akkermansia, Defluviitaleaceae_UCG-011, and Rikenella. AS-IV also modulated gut metabolites in their feces. Among 141 altered gut metabolites, amino acid production was sharply changed. Furthermore, noticeable correlations were found between several specific gut microbes and altered fecal metabolites. Conclusions: An increase of Akkermansia, Defluviitaleaceae_UCG-011, and Rikenella abundance, and modulation of amino acid metabolism, may contribute to the anti-fibrosis and cardiac protective effects of Astragaloside IV.

A theoretical study of the intermolecular interactions of H2-CuF complex: Intermolecular vibrations, isotope effects, and rotational structure.

In this paper, a theoretical study has been made on the intermolecular interactions of the H2-CuF complex, including binding energy, intermolecular vibrations, isotope effects, and rotational structure. Based on different bond lengths of H2 and CuF monomers, three intermolecular potential energy surfaces (PESs) were constructed at the level of single and double excitation coupled-cluster method with a non-iterative perturbation treatment of triple excitations [CCSD(T)] with aug-cc-pVTZ basis set supplemented with bond functions. A global minimum on the PESs show that H2-CuF complex belongs to C2ν point group with a T-shaped structure. The obtained binding energy ranges from 8890 to 10050 cm-1, which increases as the increment of H-H bond length, but opposite case has been determined as the increment of Cu-F bond length. The accuracy of PESs was examined by the available data of 101-000 transition. The predicted rotational transition frequency obtained from bound state calculations can reproduce the experimental observation very well, and the predicted error is 0.1% based on the PES1 constructed with rH2 and rCuF fixed at 0.838 and 1.7409 Å. By analyzing the wave function of the bound state, the intermolecular vibrational modes were assigned unambiguously. Isotope effects were also studied and the largest error is also 0.1% compared with the available 101-000 transition data. A set of spectroscopic parameters were obtained for six isotopologues to determine rotational structure of H2-CuF complex. Upon the complex formation, the obtained structure parameters show that H-H bond length is elongated by 0.081 Å, while Cu-F value is shortened by 0.008 Å from the respective average bond lengths of free monomer.

Add-On Effect of Honeysuckle in the Treatment of Coronavirus Disease 2019: A Systematic Review and Meta-Analysis.

Background: The outbreak of coronavirus disease 2019 (COVID-19) has rapidly spread to become a global emergency since December 2019. Chinese herbal medicine plays an important role in the treatment of COVID-19. Chinese herbal medicine honeysuckle is an extremely used traditional edible and medicinal herb. Many trials suggest that honeysuckle has obtained a good curative effect for COVID-19; however, no systematic evaluation on the clinical efficacy of honeysuckle in the treatment of COVID-19 is reported. This study aimed to evaluate the efficacy and safety of Chinese herbal medicine honeysuckle in the treatment of COVID-19. Methods: Seven electronic databases (PubMed, EMBASE, Cochrane Library, China National Knowledge Infrastructure, China Science and Technology Journal Database, Wanfang Database, and China Biology Medicine) were searched to identify randomized controlled trials (RCTs) of honeysuckle for adult patients (aged ≥ 18 years) with COVID-19. The Cochrane Risk of Bias Tool was applied to assess the methodological quality of trials. Review Manager 5.3 software was used for data analysis. Results: Overall, nine RCTs involving 1,286 patients were enrolled. Our meta-analyses found that combination therapy of honeysuckle and conventional therapy was more effective than conventional therapy alone in lung computed tomography (CT) [relative risk (RR) = 1.24, 95% confidence interval (95%CI) (1.12, 1.37), P < 0.0001], clinical cure rate [RR = 1.21, 95%CI (1.12, 1.31), P < 0.00001], and rate of conversion to severe cases [RR = 0.50, 95%CI (0.33, 0.76), P = 0.001]. Besides, combination therapy can improve the symptom score of fever, cough reduction rate, symptom score of cough, and inflammatory biomarkers (white blood cell (WBC) count; C-reactive protein (CRP)) (P < 0.05). Conclusion: Honeysuckle combined with conventional therapy may be beneficial for the treatment of COVID-19 in improving lung CT, clinical cure rate, clinical symptoms, and laboratory indicators and reducing the rate of conversion to severe cases. Besides, combination therapy did not increase adverse drug events. More high-quality RCTs are needed in the future.

Add-on effect of Chinese herbal medicine in the treatment of mild to moderate COVID-19: A systematic review and meta-analysis.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) has emerged as a global pandemic since its outbreak in Wuhan, China. It is an urgent task to prevent and treat COVID-19 effectively early. In China's experience combating the COVID-19 pandemic, Chinese herbal medicine (CHM) has played an indispensable role. A large number of epidemiological investigations have shown that mild to moderate COVID-19 accounts for the largest proportion of cases. It is of great importance to treat such COVID-19 cases, which can help control epidemic progression. Many trials have shown that CHM combined with conventional therapy in the treatment of mild to moderate COVID-19 was superior to conventional therapy alone. This review was designed to evaluate the add-on effect of CHM in the treatment of mild to moderate COVID-19. METHODS: Eight electronic databases including PubMed, EMBASE, Cochrane Central Register of Controlled Trials, the Clinical Trials.gov website, China National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database (VIP), Wanfang Database and China Biology Medicine (CBM) were searched from December 2019 to March 2021 without language restrictions. Two reviewers searched and selected studies, and extracted data according to inclusion and exclusion criteria independently. Cochrane Risk of Bias (ROB) tool was used to assess the methodological quality of the included RCTs. Review Manager 5.3.0 software was used for statistical analysis. RESULTS: Twelve eligible RCTs including 1393 participants were included in this meta-analysis. Our meta-analyses found that lung CT parameters [RR = 1.26, 95% CI (1.15, 1.38), P<0.00001] and the clinical cure rate [RR = 1.26, 95%CI (1.16, 1.38), P<0.00001] of CHM combined with conventional therapy in the treatment of mild to moderate COVID-19 were better than those of conventional therapy. The rate of conversion to severe cases [RR = 0.48, 95%CI (0.32, 0.73), P = 0.0005], TCM symptom score of fever [MD = -0.62, 95%CI (-0.79, -0.45), P<0.00001], cough cases [RR = 1.43, 95%CI (1.16, 1.75), P = 0.0006], TCM symptom score of cough[MD = -1.07, 95%CI (-1.29, -0.85), P<0.00001], TCM symptom score of fatigue[MD = -0.66, 95%CI (-1.05, -0.28), P = 0.0007], and CRP[MD = -5.46, 95%CI (-8.19, -2.72), P<0.0001] of combination therapy was significantly lower than that of conventional therapy. The WBC count was significantly higher than that of conventional therapy[MD = 0.38, 95%CI (0.31, 0.44), P<0.00001]. Our meta-analysis results were robust through sensitivity analysis. CONCLUSION: Chinese herbal medicine combined with conventional therapy may be effective and safe in the treatment of mild to moderate COVID-19. More high-quality RCTs are needed in the future.

Ascorbic acid supplementation in type 2 diabetes mellitus: A protocol for systematic review and meta-analysis.

BACKGROUND: Diabetes is one of the most common chronic diseases in the world. In recent years, with the continuous improvement of people's living standards and changes in dietary structure, the incidence of diabetes is gradually increasing. Studies have shown that ascorbic acid supplementation can reduce blood glucose, increase insulin synthesis and secretion, improve insulin resistance, and reduce the occurrence and development of complications of type 2 diabetes mellitus (T2DM). However, relevant studies have common problems such as the lack of large sample studies and low quality of included studies. Therefore, it is needed that we meta-analyze the clinical trials with high quality to elucidate the efficacy and safety of ascorbic acid supplementation in patients with T2DM. METHODS: We will search randomized controlled trials published by PubMed, Embase, the Cochrane Library, Web of Science, and the Clinical Trials.gov website from inception to August 2020 on the effects of ascorbic acid supplementation on blood glucose, glycosylated hemoglobin, serum insulin, insulin resistance and other variables in T2DM patients with no language restrictions. The retrieval adopts the combination of medical subject headings and random words, and traces the references of the included literature to supplement the acquisition of relevant literature. Two researchers will independently screen the retrieved literature, extract the data and cross-check, and the Review Manage software V5.3.0 will be utilized for meta-analysis. RESULTS: Our study will provide a high-quality and in-depth comprehensive analysis of the effects of ascorbic acid supplementation on blood glucose control, glycosylated hemoglobin and insulin resistance in type 2 diabetic patients. CONCLUSION: This systematic review and meta-analysis concerning randomized controlled trials of ascorbic acid supplementation for type 2 diabetic patients will provide a new direction and strong evidence to evaluate whether ascorbic acid supplementation is of benefit to glucose control and insulin resistance in T2DM. PROSPERO REGISTRATION NUMBER: CRD 42019146826.

Probiotics, prebiotics, and synbiotics supplementation in prediabetes: protocol for a systematic review and meta-analysis.

BACKGROUND: The prevalence of prediabetes and diabetes is increasing rapidly, and 5% to 10% of prediabetic patients will develop diabetes every year. Diabetes causes major health problems as well as a large economic burden. Human studies have demonstrated the beneficial effects of probiotics, prebiotics, and synbiotics supplementation in prediabetes. However, there are no systematic reviews that explore the therapeutic efficacy of probiotics, prebiotics, and synbiotics supplementation in patients with prediabetes. Therefore, we aim to synthesize the existing evidence evaluating the effectiveness and safety of probiotics, prebiotics, and synbiotics supplementation in prediabetic patients. METHODS: We will search PubMed, EMBASE, Cochrane Library, Web of Science, the Clinical Trials.gov website, China National Knowledge Infrastructure, China Science and Technology Journal Database, and Wanfang Data Knowledge Service Platform from inception to August 2020. Additionally, the search will be conducted in multiple languages. Search terms are keywords and medical subject headings related to prediabetes, probiotics, prebiotics, and synbiotics. The primary outcomes are differences in glycated hemoglobin and fasting blood glucose. The secondary outcomes are differences in fasting insulin, homeostasis model assessment of insulin resistance, quantitative insulin sensitivity check index, and adverse events. The meta-analysis will be performed using the Revman5.3.0 software provided by the Cochrane Collaboration. RESULTS: Our study will systematically evaluate the effectiveness and safety of probiotics, prebiotics, and synbiotics supplementation in prediabetes. CONCLUSION: The findings of this study will provide the best available evidence for probiotics, prebiotics, and synbiotics in the treatment of prediabetes, and provide a strong basis for clinical treatment.

Theoretical investigation of potential energy surface and bound states for the N2-OCS van der Waals complex.

In this work we report an ab initio intermolecular potential energy surface and theoretically spectroscopic studies for N2-OCS complex. A four-dimensional intermolecular potential energy surface (4D PES) is constructed at the level of single and double excitation coupled-cluster method with a non-iterative perturbation treatment of triple excitations [CCSD(T)] with aug-cc-pVTZ basis set supplemented with bond functions. A global minimum corresponding to a planar and nearly T-shaped structure, which has been observed experimentally, is located at R = 3.96 Å, θ1 = 8 or 172°, θ2 = 75°, φ = 180 or 0° with a well depth of 271.078 cm-1 on the potential energy surface. The local minimum corresponding to a linear geometry is also found at R = 5.06 Å, θ1 = 2 or 178°, θ2 = 179°, φ = 0 or 180° with a well depth of 224.743 cm-1. The bound state calculations have been performed for the complex by approximating the N2 and OCS molecules as the rigid rotors. The calculated structural parameters and rotational transition frequencies are in good agreement with the experimental observed values. Based on the ab initio PES, the tunneling splitting is calculated to be 0.052 cm-1 for the ground vibrational state, which can just reproduce 64% of experimental observation (0.082 cm-1). A refined method is used to calculate the tunneling splitting, and a much better result is obtained with the value of 0.094 cm-1.

The effect of zinc supplementation in pre-diabetes: A protocol for systematic review and meta-analysis.

BACKGROUND: The number of people with diabetes and pre-diabetes is growing exponentially. Human studies have shown that zinc supplementation is beneficial for pre-diabetes. However, owing to the low quality, small sample size, and methodological heterogeneity of these studies, this conclusion is not convincing. Consequently, in order to determine whether zinc supplementation is effective and safe in pre-diabetic patients, it is necessary to conduct a meta-analysis of high-quality clinical trials. METHODS: We will retrieve MEDLINE (PubMed), EMBASE, the Web of Science, Cochrane Library, and the ClinicalTrials.gov website without restriction on language. Randomized controlled trials (RCTs) of Zinc supplementation for adult patients with pre-diabetes will be searched in multiple databases from inception to October 2020. The primary outcome of the meta-analysis is the HbA1c. The secondary outcomes include the fasting blood glucose (FBG), fasting insulin (FINS), homeostasis model assessment of insulin resistance (HOMA-IR), and quantitative insulin sensitivity check index (QUICKI). Two assessors will utilize the Cochrane Collaboration's risk of bias tool to evaluate the RCTs and all statistical data will be analyzed by using the Review Manage software V5.3.0. RESULTS: This study will provide high-quality synthesis of effectiveness and safety of zinc supplementation for pre-diabetes. CONCLUSION: This systematic review and meta-analysis will provide the available evidence to assess whether the zinc supplementation is beneficial to glucose control and insulin resistance in patients with pre-diabetes. PROSPERO REGISTRATION NUMBER: CRD 42018095724.

Theoretical studies of infrared spectra for the N2-N2O complex: The tunneling effects of fundamental and combination bands.

This study is a continuation of our previously published research for the N2-N2O complex [Journal of Chemical Physics 143 (2015) 154304], and focuses on predicting the quantum tunneling effects of infrared fundamental and combination bands. A new four-dimensional intermolecular potential energy surface (PES) was constructed for the vibrational excited state upon the N2O ν1 excitation at the same calculated level with the previous PES of ground state. Compared with the ground state, two equivalent T-shaped global minima are found to be slightly different in both structural parameters and binding energies. Based on the PESs of ground and vibrational excited states, the vibrational shift of infrared spectrum for the fundamental band in the N2O ν1 region is determined to be a blue shift of 1.29 cm-1 for 14N2-N2O, which is in qualitative agreement with the experimentally observed value of 2.233 cm-1 [Journal of Chemical Physics 140 (2014) 044332]. Furthermore, for the fundamental and disrotation bands, the calculated tunneling splitting is almost the same for the ground and vibrational excited states, so the tunneling effects cannot be observed for these bands using the infrared spectroscopic technique. Nevertheless for the infrared combination bands, our calculated results suggest that the tunneling effects for the torsion and twice disrotation bands are significantly larger, and the predicted infrared spectra display obvious differences for the different sub-states. If the sensitivity of infrared spectrometer is high enough, it is interesting to investigate the quantum tunneling effects experimentally.

Theoretical studies for the infrared spectra of Ar-CO2 complex: Fundamental and combination bands.

Two potential energy surfaces (PESs) were constructed for the ground and excited states of Ar-CO2 complex at the rigid rotor approximation. Besides the notable T-shape structure, two equivalent linear structures were also found on the PES for the first time. Based on the PESs of ground and excited states, the bound state calculations were performed to determine the rotational energy levels for the ground and excited states. In combination of the experimental spectroscopic parameters of ground state and the differences of rotational energy levels, we give a theoretical prediction of infrared spectra including one fundamental band and two combination bands for two isotopomers Ar-12C16O2 and Ar-12C18O2 in the ν3 region of CO2 monomer. The predicted transition frequencies and spectroscopic parameters of excited states are in excellent agreement with the available experimental data, and these results can also be used as a guide to perform the further investigation for the infrared spectra of combination bands experimentally.