title: Calculations of PAH anions: When are diffuse functions necessary?
abstract: The effect of including vs. excluding diffuse functions while calculating numerous parameters of PAH anions by various calculation methods is discussed. The omission of diffuse functions appears to have a negligible effect while calculating geometry parameters or total energy; thus, acceptable results may be obtained without them. The conclusions for charge density appear to be the same; however, limited results make an unambiguous claim unachievable. Calculating (1)H- and (13)C-NMR shifts undoubtedly requires the use of these functions.
authors.affiliation: Department of Organic Chemistry and The Lise Meitner Minerva Center for Computational Chemistry, The Hebrew University of Jerusalem, Edmund Safra Campus, Givat Ram, Jerusalem, 91904, Israel. mordecai@vms.huji.ac.il.
authors.forename: Noach
authors.initials: N
authors.lastname: Treitel
authors.affiliation: Department of Organic Chemistry and The Lise Meitner Minerva Center for Computational Chemistry, The Hebrew University of Jerusalem, Edmund Safra Campus, Givat Ram, Jerusalem, 91904, Israel. mordecai@vms.huji.ac.il.
authors.forename: Roy
authors.initials: R
authors.lastname: Shenhar
authors.affiliation: Department of Organic Chemistry and The Lise Meitner Minerva Center for Computational Chemistry, The Hebrew University of Jerusalem, Edmund Safra Campus, Givat Ram, Jerusalem, 91904, Israel. mordecai@vms.huji.ac.il.
authors.forename: Ivan
authors.initials: I
authors.lastname: Aprahamian
authors.affiliation: Department of Organic Chemistry and The Lise Meitner Minerva Center for Computational Chemistry, The Hebrew University of Jerusalem, Edmund Safra Campus, Givat Ram, Jerusalem, 91904, Israel. mordecai@vms.huji.ac.il.
authors.forename: Tuvia
authors.initials: T
authors.lastname: Sheradsky
authors.affiliation: Department of Organic Chemistry and The Lise Meitner Minerva Center for Computational Chemistry, The Hebrew University of Jerusalem, Edmund Safra Campus, Givat Ram, Jerusalem, 91904, Israel. mordecai@vms.huji.ac.il.
authors.forename: Mordecai
authors.initials: M
authors.lastname: Rabinovitz