Positron scattering from the isoelectronic molecules N2, CO and C2H2

We report our results on the experimental total cross sections (TCSs) for positron scattering from the isoelectronic molecules N2, CO and C2H2. Where possible, for each species, comparison is made between the present results and those from earlier measurements and calculations. The agreement between the present and earlier experimental results, within the overall uncertainties on the data, is typically satisfactory for energies greater than about 8 eV, but is only marginal at lower positron impact energies. While N2, CO and C2H2 possess 14 electrons each, we find significant differences in the magnitudes of their respective TCSs and subtle differences in the energy dependence of these TCSs. These details are discussed in depth in this paper.

[1]  D. Fursa,et al.  Positron Scattering From neon and argon , 2011 .

[2]  J. Machacek,et al.  Forward angle scattering effects in the measurement of total cross sections for positron scattering , 2011 .

[3]  M. Brunger,et al.  Total cross section measurements for positron scattering from acetone , 2010 .

[4]  M. Brunger,et al.  Procedures for conditioning W- and Ni-moderators for application in positron-scattering measurements , 2010 .

[5]  K. Nixon,et al.  Low-energy positron scattering from dihydropyran. , 2009, The journal of physical chemistry. A.

[6]  M. Brunger,et al.  Electron and positron scattering from biomolecules , 2009 .

[7]  K. Nixon,et al.  Total and positronium formation cross sections for positron scattering from H2O and HCOOH , 2009 .

[8]  M. Hoshino,et al.  Cross sections for electron impact excitation of the C (1)Pi and D (1)Sigma(+) electronic states in N(2)O. , 2009, The Journal of chemical physics.

[9]  K. Nixon,et al.  Total cross sections for positron scattering from H2 at low energies , 2009 .

[10]  M. Hoshino,et al.  Integral cross sections for electron impact excitation of the 1Σ+u and 1Πu electronic states in CO2 , 2008 .

[11]  M. M. Fujimoto,et al.  Low energy elastic scattering of positrons by CO: An application of continued fractions and Schwinger variational iterative methods , 2008 .

[12]  J. Tennyson,et al.  Correlation–polarization effects in electron/positron scattering from acetylene: A comparison of computational models , 2007, 0711.4279.

[13]  M. Brunger,et al.  Total cross sections for positron scattering from benzene, cyclohexane, and aniline , 2007 .

[14]  M. Brunger,et al.  Nanoscale interactions and their applications: essays in honour of Ian McCarthy , 2007 .

[15]  M. Lima,et al.  Similarities and differences in e ± -molecule scattering: Applications of the Schwinger multichannel method , 2006 .

[16]  P. Johnson,et al.  Integral cross sections for the direct excitation of the A 3Σu+, B 3Πg, W 3Δu, B′ 3Σu−, a′ 1Σu−, a 1Πg, w 1Δu, and C 3Πu electronic states in N2 by electron impact , 2005 .

[17]  E. Bodo,et al.  Rotational cooling of molecular gases by positron impact at vanishing collision energies , 2005 .

[18]  P. Johnson,et al.  Differential cross sections for the electron impact excitation of the A 3Σu+ B 3Πhg, W3Δu, B' 3Σu-, a' 1Σu-, a 1Πg, W 1Δu, and C 3Πu states of Ν2 , 2005 .

[19]  W. Kauppila,et al.  Positron scattering by molecules , 2004 .

[20]  T. Nishimura,et al.  Computing vibrational effects in low-energy positron scattering from polyatomic molecules: the H2O and C2H2 stretching modes , 2004 .

[21]  V. Chiș,et al.  Positron impact ionization of molecular nitrogen , 2004 .

[22]  M. Lima,et al.  Electronic excitation of H{sub 2} by positron impact , 2004 .

[23]  M. Lima,et al.  Elastic positron scattering by C{sub 2}H{sub 2}: Differential cross sections and virtual state formation , 2003 .

[24]  F. Gianturco,et al.  Low-energy positron dynamics in small hydrocarbon gases , 2003 .

[25]  D. Leslie,et al.  Production of collimated positronium from molecular nitrogen , 2002 .

[26]  Stephen Buckman,et al.  Electron-molecule scattering cross-sections. I. Experimental techniques and data for diatomic molecules , 2002 .

[27]  C. Surko,et al.  Search for resonances in the scattering of low-energy positrons from atoms and molecules , 2001 .

[28]  J. Sullivan,et al.  Excitation of electronic states of Ar, H(2), and N(2) by positron impact. , 2001, Physical review letters.

[29]  M. Lima,et al.  Annihilation probability density in positron scattering by He , 2001 .

[30]  M. Lima,et al.  Progress with the Schwinger multichannel method in positron- molecule scattering , 2000 .

[31]  W. Kauppila,et al.  Measurements of differential cross sections for positrons scattered from N 2 , CO, O 2 , N 2 O, and CO 2 , 1999 .

[32]  F. Gianturco,et al.  Positron scattering from polar molecules: Rotovibrationally inelastic collisions with CO targets , 1997 .

[33]  F. Gianturco,et al.  Dynamical coupling effects in the vibrational excitation of H 2 sand N 2 scolliding with positrons , 1997 .

[34]  M. Brunger,et al.  Low energy electron scattering from CO: absolute cross section measurements and R -matrix calculations , 1996 .

[35]  S. Nakagawa.  Anisotropic contribution in multicenter polarizabilities and first hyperpolarizabilities. Ab initio MP2 calculations of acetylene, ethylene, ethane and benzene , 1995 .

[36]  H. Ehrhardt,et al.  Rotational excitation of diatomic molecules at intermediate energies: absolute differential state-to-state transition cross sections for electron scattering from N2, Cl2, CO and HCl , 1995 .

[37]  Morrison,et al.  Detailed theoretical and experimental analysis of low-energy electron-N2 scattering. , 1995, Physical review. A, Atomic, molecular, and optical physics.

[38]  O. Sueoka,et al.  Total cross section measurements for positrons and electrons colliding with molecules. II. HCl , 1994 .

[39]  O. Sueoka,et al.  Total Cross-Section Measurements for 0.3–10 eV Positron Scattering on N2, CO, and CO2 Molecules , 1993 .

[40]  A. G. Middleton,et al.  Vibrational excitation in isoelectronic molecules by electron impact : CO and N2 , 1992 .

[41]  M. Plummer,et al.  Low-energy e+-N2 scattering calculations using the Kohn variational method , 1991 .

[42]  J. Tennyson,et al.  R-matrix calculations of vibrationally resolved positron-N2 scattering cross sections , 1991 .

[43]  A. Jain.  A treatment of low-energy positron-CO collisions using a new parameter-free positron correlation polarisation (PCOP) potential , 1990 .

[44]  M. Spackman.  Accurate prediction of static dipole polarizabilities with moderately sized basis sets , 1989 .

[45]  O. Sueoka,et al.  Total cross section measurements for 1-400 eV positrons and electrons in C2H2 , 1989 .

[46]  B. Saha,et al.  Non-adiabaticity and other aspects of polarisation in positron-molecule scattering , 1989 .

[47]  Hsieh,et al.  Total-cross-section measurements for positron and electron scattering by O2, CH , 1988, Physical review. A, General physics.

[48]  I. Kanik,et al.  Absolute elastic differential electron scattering cross sections for carbon monoxide and molecular nitrogen in the intermediate energy region , 1988 .

[49]  J. Tennyson,et al.  Rotational and polarisation effects in low-energy positron-CO collisions using the R-matrix method , 1987 .

[50]  A. Jain.  Positron-CO scattering below the positronium threshold , 1986 .

[51]  O. Sueoka,et al.  Total Cross-Sections for Positrons and Electrons Colliding with N2, CO and CO2 Molecules , 1984 .

[52]  W. Kauppila,et al.  e(-CO and e(-CO/sub 2/ total cross-section measurements , 1983 .

[53]  M. Charlton,et al.  Total scattering cross sections for low-energy positrons in the molecular gases H2, N2, CO2, O2 and CH4 , 1983 .

[54]  W. Kauppila,et al.  Measurements of total scattering cross sections for intermediate-energy positrons and electrons colliding with helium, neon, and argon , 1981 .

[55]  E. S. Gillespie,et al.  Positron scattering by molecular nitrogen , 1975 .

[56]  J. Muenter,et al.  Electric dipole moment of carbon monoxide , 1975 .

[57]  J. Darewych,et al.  Interaction of low-energy positrons with molecular nitrogen , 1974 .

[58]  R. C. Weast.  CRC Handbook of Chemistry and Physics , 1973 .

[59]  T. Takaishi,et al.  Thermal transpiration effect of hydrogen, rare gases and methane , 1963 .