title: Ground state structures and excited state dynamics of pyrrole-water complexes: ab initio excited state molecular dynamics simulations.
abstract: Structures of the ground state pyrrole-(H2O)n clusters are investigated using ab initio calculations. The charge-transfer driven femtosecond scale dynamics are studied with excited state ab initio molecular dynamics simulations employing the complete-active-space self-consistent-field method for pyrrole-(H2O)n clusters. Upon the excitation of these clusters, the charge density is located over the farthest water molecule which is repelled by the depleted pi-electron cloud of pyrrole ring, resulting in a highly polarized complex. For pyrrole-(H2O), the charge transfer is maximized (up to 0.34 a.u.) around approximately 100 fs and then oscillates. For pyrrole-(H2O)2, the initial charge transfer occurs through the space between the pyrrole and the pi H-bonded water molecule and then the charge transfer takes place from this water molecule to the sigma H-bonded water molecule. The total charge transfer from the pyrrole to the water molecules is maximized (up to 0.53 a.u.) around approximately 100 fs.
authors.affiliation: Department of Chemistry, Pohang University of Science and Technology, San 31, Hyojadong, Namgu, Pohang 790-784, Korea.
authors.forename: Anupriya
authors.initials: A
authors.lastname: Kumar
authors.forename: Maciej
authors.initials: M
authors.lastname: Kołaski
authors.forename: Kwang S
authors.initials: KS
authors.lastname: Kim