[Clinical epidemiological characteristics of pertussis in children and the status of infection in their close contacts]

Objective: To investigate the clinical epidemiological characteristics of children with pertussis and the infection of their close contacts. Methods: The clinical data of children with pertussis and the etiological detection results of close contacts in Shenzhen Children's Hospital from 2015 to 2018 were collected and descriptive epidemiological analysis was carried out. Results: The cases of pertussis from 2015 to 2018 were reported as 504, 425, 796 and 991 respectively, with a total of 2 716 cases. The most cases was in May in 2015 (72 cases), in August in 2016 and 2018 (68 cases and 144 cases), and in July in 2017 (115 cases). A total of 1 517 male and 1 199 female children were reported from 2015 to 2018, the ratio of male-to-female was 1.3∶1. The proportion of children under 1 year old was 79.7% (2 165/2 716), of which 74.4% (1 610/2 165) was less than 6 months old. Among the reported cases, 1 605 (59.1%) were treated as outpatients, aged M(Q₁,Q₃) 5 (3, 11) months, and 1 111 (40.9%) were hospitalized, aged 4 (2, 7) months. There were 876 outpatients (54.4%) and 734 inpatients (45.6%) under 6 months of age, 575 outpatients (63.5%) and 331 inpatients (36.5%) between 6 months and 2 years of age, and 154 outpatients (77.0%) and 46 inpatients (23.0%) with above 2 years old, respectively. There were statistically significant differences between the two treatment methods in different age groups (P<0.001). The average hospitalization time of inpatients under 6 months of age was (8.5±3.9) days, that of inpatients between 6 months and 2 years of age was (7.1±3.7) days, and that of inpatients above 2 years old was (6.8±3.3) days. The difference was statistically significant (P<0.001). The etiological test results of pertussis were collected from 617 close contacts of 270 reported cases, the positive detection rate of mothers was the highest (34.9%). Conclusions: From 2015 to 2018, the number of reported cases of pertussis in our hospital fluctuated and increased year by year, with high incidence in summer, mainly in children under 1 year old, and more males than females. Outpatient treatment was more than inpatient treatment, its age was obviously older than the latter. The younger the children, the higher the proportion of hospitalization, and with the increase of the age, the hospitalization time was obviously shortened. Among the close family contacts, the mother might be the main source of pertussis infection in children.

[Clinical characteristics and related factors of human respiratory syncytial viruses infection in premature infants within 2 years after birth in Shenzhen Children's Hospital]

Objective: To analyze the clinical characteristics and factors associated with human respiratory syncytial virus (HRSV) infection in preterm infants within the first 2 years of life. Methods: Children with respiratory tract infections admitted to Shenzhen Children's Hospital during the 3-year period from January 2016 to December 2018 who were <2 years old and whose gestational age at birth was <37 weeks were selected, and those who met the diagnostic criteria for RSV infection were categorized as the positive case group, and those who had no detectable influenza virus, parainfluenza virus and adenovirus antigens were categorized as the negative group. The clinical characteristics of the case group were retrospectively analyzed. A multivariable logistic regression model was used to analyze the associated factors. Results: A total of 1, 483 children were included, of whom 149 (10.1%) were HRSV positive (case group) and 447 (30.1%) were in the negative group (control group). In the case group, there were 88 (59.1%) male and 61 (40.1%) female children; 127 children (85.2%) in the mild-to-moderate disease group and 22 children (14.8%) in the severe disease group. The number of cases in the severe disease group was greater than that in the mild-to-moderate disease group [(17 cases, 77.3%) than (59 cases, 46.5%)], with statistical significance (P=0.010). A total of 117 cases (78.5%) had onset from February to July. Multivariable analysis showed that males [OR (95%CI) of 0.105 (0.013-0.112)], age at month [0.045 (0.036-0.112)], congenital heart disease [0.388 (0.206-0.940)] and bronchopulmonary dysplasia [0.622 (0.484-0.927)] were positively associated with HRSV infection in preterm infants. Conclusion: The high prevalence of HRSV infection in preterm infants in Shenzhen is from February to July each year, and male children are more common. Young age, congenital heart disease and bronchopulmonary dysplasia are all independent risk factors for HRSV infection in preterm infants.

[A multicentric study on clinical characteristics and antibiotic sensitivity in children with methicillin-resistant Staphylococcus aureus infection]

Objective: To investigate the clinical characteristics of pediatric methicillin-resistant Staphylococcus aureus (MRSA) infection and the antibiotic sensitivity of the isolates. Methods: The clinical data of children with MRSA infection and antibiotic sensitivity of the isolates from 11 children's hospitals in Infectious Diseases Surveillance of Paediatrics (ISPED) group of China between January 1, 2018 and December 31, 2018 were collected retrospectively. The children's general condition, high-risk factors, antimicrobial therapy and prognosis, differences in clinical disease and laboratory test results between different age groups, and differences of antibiotic sensitivity between community-acquired (CA)-MRSA and hospital-acquired (HA)-MRSA were analyzed. The t test and Wilcoxon rank sum test were used for statistical analysis of the quantitative data and Chi-square test were used for comparison of rates. Results: Among the 452 patients, 264 were males and 188 were females, aged from 2 days to 17 years. There were 233 cases (51.5%) in the ≤1 year old group, 79 cases (17.5%) in the>1-3 years old group, 29 cases (6.4%) in the >3-5 years old group, 65 cases (14.4%) in the >5-10 years old group, and 46 cases (10.2%) in the>10 years old group. The main distributions of onset seasons were 55 cases (12.2%) in December, 47 cases (10.4%) in February, 46 cases (10.2%) in November, 45 cases (10.0%) in January, 40 cases (8.8%) in March. There were 335 cases (74.1%) CA-MRSA and 117 (25.9%) cases HA-MRSA. Among all cases, 174 cases (38.5%) had basic diseases or long-term use of hormone and immunosuppressive drugs. During the period of hospitalization, 209 cases (46.2%) received medical interventions. There were 182 patients (40.3%) had used antibiotics (β-lactams, glycopeptides, macrolides, carbapenems, oxazolones, sulfonamides etc) 3 months before admission. The most common clinical disease was pneumonia (203 cases), followed by skin soft-tissue infection (133 cases), sepsis (92 cases), deep tissue abscess (42 cases), osteomyelitis (40 cases), and septic arthritis (26 cases), suppurative meningitis (10 cases). The proportion of pneumonia in the ≤1 year old group was higher than the >1-3 years old group,>3-5 years old group,>5-10 years old group,>10 years old group (57.5% (134/233) vs. 30.4% (24/79), 31.0% (9/29), 38.5% (25/65), 23.9% (11/46), χ(2)=17.374, 7.293, 7.410, 17.373, all P<0.01) The proportion of skin and soft tissue infections caused by CA-MRSA infection was higher than HA-MRSA (33.4% (112/335) vs. 17.9% (21/117), χ(2)=10.010, P=0.002), and the proportion of pneumonia caused by HA-MRSA infection was higher than CA-MRSA (53.0% (62/117) vs. 42.1% (141/335), χ(2)=4.166, P=0.041). The first white blood cell count of the ≤1 year old group was higher than that children > 1 year old ((15±8)×10(9)/L vs. (13±7)×10(9)/L, t=2.697, P=0.007), while the C-reactive protein of the ≤1 year old group was lower than the 1-3 years old group,>5-10 years old group,>10 years old group (8.00 (0.04-194.00) vs.17.00 (0.50-316.00), 15.20 (0.23-312.00), 21.79(0.13-219.00) mg/L, Z=3.207, 2.044, 2.513, all P<0.05), there were no significant differences in procalcitonin (PCT) between different age groups (all P>0.05). After the treatment, 131 cases were cured, 278 cases were improved, 21 cases were not cured, 12 cases died, and 10 cases were abandoned. The 452 MRSA isolates were all sensitive to vancomycin (100.0%), linezolid (100.0%), 100.0% resistant to penicillin, highly resistant to erythromycin (85.0%, 375/441), clindamycin (67.7%, 294/434), less resistant to sulfonamides (5.9%, 23/391), levofloxacin (4.5%, 19/423), gentamicin (3.2%, 14/438), rifampicin (1.8%, 8/440), minocycline (1.1%, 1/91). The antimicrobial resistance rates were not significantly different between the CA-MRSA and HA-MRSA groups (all P>0.05). Conclusions: The infection of MRSA is mainly found in infants under 3 years old. The prevalent seasons are winter and spring, and MRSA is mainly acquired in the community. The main clinical diseases are pneumonia, skin soft-tissue infection and sepsis. No MRSA isolate is resistant to vancomycin, linezolid. MRSA isolates are generally sensitive to sulfonamides, levofloxacin, gentamicin, rifampicin, minocycline, and were highly resistant to erythromycin and clindamycin. To achieve better prognosis. clinicians should initiate anti-infective treatment for children with MRSA infection according to the clinical characteristics of patients and drug sensitivity of the isolates timely and effectively.

[Guidelines for the use of post-traumatic tetanus vaccines and passive immune preparation]

Post-traumatic tetanus is the main type of non-neonatal tetanus. To reduce the incidence and mortality rateof tetanus and guide the primary medical institutions to prevent and control tetanus after trauma, the National Immunization Planning Technical Working Group of the Chinese Center for Disease Control and Prevention has compiled this document in the reference with Position Paper by World Health Organization, and the latest research progress both at home and abroad. The guidelines focus on the basic procedures for the prevention and treatment of post-traumatic tetanus, the application of tetanus vaccines and immune preparation, and pre-exposure immunization in high-risk populations of trauma.

[Guidelines for the use of post-traumatic tetanus vaccines and passive immune preparation]

Post-traumatic tetanus is the main type of non-neonatal tetanus. To reduce the incidence and mortality rate of tetanus and guide the primary medical institutions to prevent and control tetanus after trauma, National Immunization Planning Technical Working Group of the Chinese Center for Disease Control and Prevention has compiled this document in the reference with Position Paper by World Health Organization, the latest research progress from home and abroad. The guidelines focus on the basic procedures for the prevention and disposition of post-traumatic tetanus, the application of tetanus vaccines and immune preparation, and the pre-exposure immunization in high-risk populations of trauma.

[A multicentric clinical study on clinical characteristics and drug sensitivity of children with pneumococcal meningitis in China]

Objective: To understand clinical characteristics of children with pneumococcal meningitis (PM) in China and to analyze the drug sensitivity of Streptococcus pneumoniae isolates and associated impacts on death and sequelae. Methods: The clinical data, follow-up results and antimicrobial sensitivity of isolated strains of 155 children (including 98 males and 57 females, age ranged from 2 months to 15 years) with PM in 10 tertiary-grade A class hospitals of Infectious Diseases Surveillance of Pediatrics (ISPED) from 2013 to 2017 were collected and analyzed retrospectively. Patients were divided into different groups according to the following standards: ≤1 year old group,>1-3 years old group and >3 years old group according to age; death group and non-death group according to the death within 30 days after PM diagnosis; complication group and non-complication group according to the abnormal cranial imaging diagnosis; sequelae group and no-sequelae group according to the follow-up results. Bonfereoni chi-square segmentation and Kruskal-Wallis H test were used for statistical analysis. Results: There were 64 cases (41.3%) in the ≤1 year old group, 39 cases in the >1-3 years old group (25.2%), and 52 cases (33.5%) in the >3 years old group. The most common clinical manifestation was fever (151 cases, 97.4%). The mortality was 16.8% (26/155) during hospitalization. The neurological complication rate was 49.7% (77/155) during hospitalization, including the most common complication, subdural effusion and (or) empyema in 50 cases (32.3%) and hearing impairment in 6 cases. During follow-up after discharge, no death was found and focal neurological deficits were found in 47 cases (30.3%), including the frequent neurological sequelae: cognitive and mental retardation of different degree in 22 cases and hearing impairment in 14 cases (9.0%). The rate of cure and improvement on discharge was 74.8% (116/155) and the lost to follow-up rate was 8.4% (13/155). The proportions of died cases, neurological complications during hospitalization and proportions of peripheral white blood cell count <12 × 10(9)/L before admission in ≤1 year old group were significantly higher than those in >3 years old group (25.0% (16/64) vs. 5.8% (3/52), 75.0% (48/64) vs. 25.0% (13/52), 48.4% (31/64) vs. 15.4% (8/52), χ(2)=7.747, 28.767, 14.044; P=0.005, 0.000, 0.000). The proportions of headache, vomiting, neck resistance and high risk factors of purulent meningitis in >3 years old group were significantly higher than those in ≤ 1 year old group (67.3%(35/52) vs. 1.6%(1/64), 80.8% (42/52) vs. 48.4% (31/64), 69.2% (36/52) vs. 37.5% (24/64), 55.8% (29/52) vs. 14.1%(9/64), χ(2)=57.940, 12.856, 11.568, 22.656; P=0.000, 0.000, 0.001, 0.000). Streptococcus pneumoniae isolates were completely sensitive to vancomycin (100.0%, 152/152), linezolid (100.0%, 126/126), moxifloxacin (100.0%, 93/93) and ofloxacin (100.0%,41/41); highly sensitive to levofloxacin (99.3%, 142/143) and ertapenem (84.6%, 66/78); moderately sensitive to ceftriaxone (48.4%, 45/93), cefotaxime (40.0%, 44/110) and meropenem (38.0%, 38/100); less sensitive to penicillin (19.6%, 27/138) and erythromycin (4.2%, 5/120). The proportions of non-sensitive strains of penicillin (21/21) and meropenem (17/18) in the death group were significantly higher than those (90/117, 45/82) in the survived group(χ(2)=4.648 and 9.808, P=0.031 and 0.002). Conclusions: The children's PM is mainly found in infants under 3 years old in China. Death and neurological complications are more common in PM children under 1 year old. The clinical manifestations and peripheral blood inflammatory markers of PM patients under 1 year old are not typical. Fever is the most common clinical manifestation and subdural effusion and (or) empyema is the most common complication. Long-term hearing impairment is common in PM and the follow-up time must be prolonged. The dead PM cases had high in sensitive rates to penicillin and meropenem.

[Clinical analysis of 309 hospitalized children with pertussis-associated pneumonia]

Objective: To investigate the clinical characteristics of pertussis-associated pneumonia and analyze it's risk factors. Methods: Clinical data were taken from Shenzhen Children's Hospital with Bordetella pertussis infection and confirmed by culture or real-time polymerase chain reaction (PCR) of nasopharyngeal secretion from October 2013 to December 2015. Patients were divided into two groups, those with radiologically confirmed pneumonia in the course of their disease and those with not. Clinical data were retrospectively analyzed and compared. T test, Rank sum test or chi square test were used for comparison between groups. Risk factors were analyzed by unconditional Logistic regression analysis. Results: A total of 501 children hospitalized with Bordetella pertussis infection were included. Among them, 309 patients were diagnosed with pneumonia. The median age was 3 (2, 6) months. Symptoms were paroxysmal cough (n=252, 81.6%), tachypnea (n=69, 22.3%), and cyanosis (n=105, 34.0%). The time from onset of cough to radiologically confirmed pneumonia was between 1 and 66 days with a median of 9 (5.5, 15.0) days. The most common pathogen of coinfection was respiratory syncytial virus (RSV)(20 cases). Macrolides were used in 306 cases for (8.2±3.6) days. All cases showed significant improvement. There were more male children (62.1% (192/309) vs. 50.3% (95/189) , χ(2)=6.768, P=0.009), and more instances of comorbidities (13.3% (41/309) vs.5.8% (11/189) , χ(2)=6.957, P=0.008) in the pneumonia group than in the other. The age was younger (3 (2,6) vs.4 (2,6) months, Z=32.91, P=0.000) in pneumonia group than in the other. Male sex, younger age, and underlying disease were independent risk factors for pertussis-associated pneumonia (OR=1.648, 1.486, 2.695, P=0.008, 0.036, 0.005). Conclusions: Pneumonia, as a complication of pertussis, is very easy to see in hospitalized children. The duration of hospitalization is extensive. It is more likely to happen in children who are male, young, and having underlying diseases. Pneumonia is easy to occur in the first 2 weeks of the course of disease.

[Clinical characteristics and antimicrobial resistance of pneumococcal infections from 9 children's hospitals in 2016]

Objective: To describe the clinical characteristics of pneumococcal infections and drug resistance of Streptococcus pneumoniae isolates from children's hospitals, which would provide reference for preventing and treating pneumococcal diseases. Methods: This was a prevalence survey. In this study, the age, specimen type, monthly distribution characteristics, and antimicrobial resistance of Streptococcus pneumoniae isolates from 9 children's hospitals in China were investigated between January 1, 2016 and December 31, 2016. The WHONET 5.6 software was used to analyze the antibiotic susceptibility of Streptococcus pneumoniae. The comparison of rates was performed by Chi-square test. Results: A total of 6 200 isolates of streptococcus pneumoniae were obtained, namely, 95.1% (5 876/6 177) from the respiratory tract specimens, 2.2% (136/6 177) from blood specimens and 0.4% (24/6 177) from cerebrospinal fluid specimens. The isolates were mainly from children older than 1 and younger than 5 years (54.7%, 3 381/6 185) . Most of strains (33.2%, 1 184/3 563) were isolated in November, December and January. Streptococcus pneumoniae isolates were completely sensitive to vancomycin (100.0%, 6 189/6 189) , linezolid (100.0%, 6 030/6 030) , moxifloxacin (100.0%, 3 064/3 064) , highly sensitive to levofloxacin (99.8%, 5 528/5 540), ertapenem (98.8%, 3 024/3 061) and lowly sensitive to erythromycin (1.7%, 102/6 016), clindamycin (3.7%, 116/3 136), and tetracycline (5%, 244/4 877), respectively. According to the parenteral susceptibility breakpoints for non-meningitis isolates, the sensitivity of Streptocococus pneumoniae to penicillin from children's hospital of Chongqing Medical University (49.3%, 892/1 809) was significantly lower than those of other hospitals (χ(2)=1 268.161, P<0.05) . Conclusions:Streptococcus pneumoniae is mainly isolated from respiratory tract, from children older than 1 and younger than 5 years and during November to January in tertiary children's hospital of China. The Streptococcus pneumoniae from children is highly sensitive to vancomycin, linezolid, moxifloxacin, levofloxacin. There are also significant differences in the sensitivity of penicillin for Streptococcus pneumoniae from different hospitals.

[Autophagy and phenotypic modulation of corpus cavernosum smooth muscle cells in hypoxia-induced erectile dysfunction]

The correlation between hypoxia and erectile dysfunction (ED) has been universally acknowledged for decades in the academic world. The phenotypic modulation of corpus cavernosum smooth muscle cells (CCSMCs) is regarded as one of the factors of hypoxia-induced ED, but the underlying mechanisms remain unclear. Recent researches show some correlation between autophagy and phenotypic modulation of CCSMCs, which may be associated with the overexpressions of PDGF, TGF-β, and vasoactive factors in the organism following hypoxia.

[Microstructural changes of the corpus cavernosum in hypoxia-induced erectile dysfunction]

Hypoxia is an independent risk factor of erectile dysfunction (ED), and the mechanisms of hypoxia causing ED are varied and complicated. Traditional studies related are concentrated on the changes of the corpus cavernosal endothelium and hormone levels in the body but have failed to achieve notable breakthroughs. Recent researches have demonstrated that such alterations in the corpus cavernosal microstructure as decreased corpus cavernosum smooth muscle cells of the contractile phenotype and fibrillation of the corpus cavernosum may be two important factors of hypoxia-induced ED. This review gives a brief introduction of the management of hypoxia-induced ED with the strategies of intervening in the corpus cavernosal microstructural changes, such as gene therapy, stem cell therapy, and induction of cell autophagy.

The Jahn-Teller effect in the electron momentum spectroscopy of ammonia

The 1e and 3a(1) bands of the ammonia molecule have been studied using the high-resolution electron momentum spectroscopy at impact energies of 1200 and 600 eV. Several slices of 1e and 3a(1) bands in the different binding energy ranges were selected, and their electron-momentum distributions were carefully compared. The discernable difference among the distributions of the selected slices of the 1e band shows that the Jahn-Teller effect indeed influences the electron momentum distribution of the 1e orbital of ammonia.

Vibrational effects on the electron momentum distributions of valence orbitals of formamide

The ionization energy spectra and electron momentum distributions of formamide were investigated using the high-resolution electron momentum spectrometer in combination with high level calculations. The observed ionization energy spectra and electron momentum distributions were interpreted using symmetry adapted cluster-configuration interaction theory, outer valence Green function, and DFT-B3LYP methods. The ordering of 10a(') and 2a(") orbitals of formamide was assigned unambiguously by comparing the experimental electron momentum distributions with the corresponding theoretical results, i.e., 10a(') has a lower binding energy. In addition, it was found that the low-frequency wagging vibration of the amino group at room temperature has noticeable effects on the electron momentum distributions. The equilibrium-nuclear-positions-approximation, which was widely used in electron momentum spectroscopy, is not accurate for formamide molecule. The calculations based on the thermal average can evidently improve the agreement with the experimental momentum distributions.

Imaging Momentum Orbital Densities of Conformationally Versatile Molecules: A Benchmark Theoretical Study of the Molecular and Electronic Structures of Dimethoxymethane

The main purpose of the present work is to predict from benchmark many-body quantum mechanical calculations the results of experimental studies of the valence electronic structure of dimethoxymethane employing electron momentum spectroscopy, and to establish once and for all the guidelines that should systematically be followed in order to reliably interpret the results of such experiments on conformationally versatile molecules. In a first step, accurate calculations of the energy differences between stationary points on the potential energy surface of this molecule are performed using Hartree-Fock (HF) theory and post-HF treatments of improving quality (MP2, MP3, CCSD, CCSD(T), along with basis sets of increasing size. This study focuses on the four conformers of this molecule, namely the trans-trans (TT), trans-gauche (TG), gauche-gauche (G+G+), and gauche-gauche (G+G-) structures, belonging to the C2v, C1, C2, and Cs symmetry point groups, respectively. A focal point analysis supplemented by suited extrapolations to the limit of asymptotically complete basis sets is carried out to determine how the conformational energy differences at 0 K approach the full CI limit. In a second step, statistical thermodynamics accounting for hindered rotations is used to calculate Gibbs free energy corrections to the above energy differences, and to evaluate the abundance of each conformer in the gas phase. It is found that, at room temperature, the G+G+ species accounts for 96% of the conformational mixture characterizing dimethoxymethane. In a third step, the valence one-electron and shake-up ionization spectrum of dimethoxymethane is analyzed according to calculations on the G+G+ conformer alone by means of one-particle Green's function [1p-GF] theory along with the benchmark third-order algebraic diagrammatic construction [ADC(3)] scheme. A complete breakdown of the orbital picture of ionization is noted at electron binding energies above 22 eV. A comparison with available (e,2e) ionization spectra enables us to identify specific fingerprints of through-space orbital interactions associated with the anomeric effect. At last, based on our 1p-GF/ADC(3) assignment of spectral bands, accurate and spherically averaged (e,2e) electron momentum distributions at an electron impact energy of 1200 eV are computed from the related Dyson orbitals. Very significant discrepancies are observed with momentum distributions obtained for several outer-valence levels using standard Kohn-Sham orbitals.

Investigation of valence orbitals of propene by electron momentum spectroscopy

The binding energy spectra and momentum distributions of all valence orbitals of propene were studied by electron momentum spectroscopy (EMS) as well as Hartree-Fock and density functional theoretical calculations. The experiment was carried out at impact energies of 1200 eV and 600 eV on the state-of-the-art EMS spectrometer developed at Tsinghua University recently. The experimental momentum profiles of the valence orbitals were obtained and compared with the various theoretical calculations. Moreover, the experiment with a new analysis method presents a strong support for the correct ordering of the orbital 8a' and 1a'', i.e., 9a' < 8a' < 1a'' < 7a'.

Direct observation of distorted wave effects in ethylene using the (e,2e) reaction

We report here the direct measurements of electron momentum distributions for ethylene using the (e,2e) reaction at different impact energies from 400 to 2400 eV. The "turn up" effects in the (e,2e) cross sections of the 1b(3g) orbital compared with the plane-wave impulse approximation calculations were observed at low and high momentum regions, and such discrepancies become smaller with the increase of the impact electron energies. It is suggested that the observed discrepancies are due to the distorted-wave effects in molecules, while appropriate theoretical calculations using distorted waves in molecules could not be achieved until now.

An investigation of valence shell orbital momentum profiles of difluoromethane by binary (e,2e) spectroscopy

The electron binding energy spectra and momentum profiles of the valence orbitals of difluoromethane, also known as HFC32 (HFC-hydrofluorocarbon) (CH(2)F(2)), have been studied by using a high resolution (e,2e) electron momentum spectrometer, at an impact energy of 1200 eV plus the binding energy, and by using symmetric noncoplanar kinematics. The experimental momentum profiles of the outer valence orbitals and 4a(1) inner valence orbital are compared with the theoretical momentum distributions calculated using Hartree-Fock and density functional theory (DFT) methods with various basis sets. In general, the shapes of the experimental momentum distributions are well described by both the Hartree-Fock and DFT calculations when large and diffuse basis sets are used. However, the result also shows that it is hard to choose the different calculations for some orbitals, including the methods and the size of the basis sets employed. The pole strength of the ionization peak from the 4a(1) inner valence orbital is estimated.

The outer valance orbital electron densities of cyclopentane by binary (e,2e) spectroscopy

The binding energy spectra and electron distributions in momentum space of the valence orbitals of cyclopentane (C(5)H(10)) are studied by Electron Momentum Spectroscopy (EMS) in a noncoplanar symmetric geometry. The impact energy was 1200 eV plus binding energy and energy resolution of the EMS spectrometer was 1.2 eV. The experimental momentum profiles of the outer valence orbitals are compared with the theoretical momentum distributions calculated using Hartree-Fock and density functional theory (DFT) methods. The shapes of the experimental momentum distributions are generally quite well described by both the Hartree-Fock and DFT calculations when the large and diffuse basis sets are used.