Role of Nonvalence States in the Ultrafast Dynamics of Isolated Anions.

Nonvalence states of neutral molecules (Rydberg states) play important roles in nonadiabatic dynamics of excited states. In anions, such nonadiabatic transitions between nonvalence and valence states have been much less explored even though they are believed to play important roles in electron capture and excited state dynamics of anions. The aim of this Feature Article is to provide an overview of recent experimental observations, based on time-resolved photoelectron imaging, of valence to nonvalence and nonvalence to valence transitions in anions and to demonstrate that such dynamics may be commonplace in the excited state dynamics of molecular anions and cluster anions.

Spectroscopic Determination of an Anion-π Bond Strength.

The anion-π bond has emerged as an important nonvalence interaction in supramolecular and biological structure. Although recognized as a strong noncovalent interaction, driven by electrostatic charge-quadrupole moment and correlation interactions, benchmark experimental and computational studies on the intrinsic anion-π bond strength are scarce. Here, we present a gas-phase photoelectron spectroscopic study on the archetypical iodide-hexafluorobenzene anion-π bonded complex.

Photoelectron Spectroscopy of the Hexafluorobenzene Cluster Anions: (CF) ( n = 1-5) and I(CF).

Frequency-resolved (2D) photoelectron (PE) spectra of the anionic clusters (CF) , for n = 1-5, and time-resolved PE spectra of ICF are presented using a newly built instrument and supported by electronic structure calculations. From the 2D PE spectra, the vertical detachment energy (VDE) of CF was measured to be 1.60 ± 0.

Evidence of Electron Capture of an Outgoing Photoelectron Wave by a Nonvalence State in (CF) .

Frequency-resolved photoelectron spectra are presented for (CF) with n = 1-5 that show that CF is solvated by neutral CF molecules. Direct photodetachment channels of CF are observed for all n, leaving the neutral in the S ground state or triplet states, T and T. For n ≥ 2, an additional indirect electron loss channel is observed when the triplet-state channels open.

Ultrafast dynamics of low-energy electron attachment via a non-valence correlation-bound state.

The primary electron-attachment process in electron-driven chemistry represents one of the most fundamental chemical transformations with wide-ranging importance in science and technology. However, the mechanistic detail of the seemingly simple reaction of an electron and a neutral molecule to form an anion remains poorly understood, particularly at very low electron energies. Here, time-resolved photoelectron imaging was used to probe the electron-attachment process to a non-polar molecule using time-resolved methods.

Molecular mapping of five soybean genes involved in male-sterility, female-sterility.

In soybean, asynaptic and desynaptic mutants lead to abnormal meiosis and fertility reduction. Several male-sterile, female-sterile mutants have been identified and studied in soybean, however, some of these mutants have not been mapped to locations on soybean chromosomes. The objectives of this study were to molecularly map five male-sterile, female-sterile genes (st2, st4, st5, st6, and st7) in soybean and compare the map locations of these genes with already mapped sterility genes.

Segregation distortion in a region containing a male-sterility, female-sterility locus in soybean.

In diploid segregation, each alternative allele has a 50% chance of being passed on to the offspring. Mutations in genes involved in the process of meiotic division or early stages of reproductive cell development can affect allele frequency in the gametes. In addition, competition among gametes and differential survival rates of gametes can lead to segregation distortion.