Optical characterization of platinum-halide ladder compounds

TL;DR

This paper investigates new platinum-halide ladder compounds, modeling their optical properties with a multiband Hamiltonian, and identifies their distinct electronic structures and valence arrangements through theoretical spectra reproduction.

Contribution

It introduces and characterizes two novel platinum-halide ladder compounds with distinct valence arrangements using theoretical optical conductivity analysis.

Findings

Polarized optical spectra are successfully reproduced theoretically.

Ground-state valence distributions are reasonably determined.

Distinct interchain valence arrangements are identified for the two compounds.

Abstract

New varieties of quasi-one-dimensional halogen (X)-bridged transition-metal (M) complexes, (C_8_H_6_N_4_)[Pt(C_2_H_8_N_2_)X]_2_X(ClO_4_)_3_\cdotH_2_O (X=Br,Cl) and (C_10_H_8_N_2_)[Pt(C_4_H_13_N_3_)Br]_2_Br_4_\cdot2H_2_O, comprising two-leg ladders of mixed-valent platinum ions, are described in terms of a multiband extended Peierls-Hubbard Hamiltonian. The polarized optical conductivity spectra are theoretically reproduced and the ground-state valence distributions are reasonably determined. The latter variety, whose interchain valence arrangement is out of phase, is reminiscent of conventional MX single-chain compounds, while the former variety, whose interchain valence arrangement is in phase, reveals itself as a novel d-p-\pi-hybridized multiband ladder material.