Theoretical analysis of conjugated polymers with a degenerate ground state: Type‐I and type‐II soliton charge storage states in poly(1,6‐heptadiyne) and derivatives

1995 ◽  
Vol 103 (10) ◽  
pp. 4201-4210 ◽  
Author(s):  
M. Lögdlund ◽  
J. L. Brédas
Keyword(s):  
Theoretical Analysis ◽  
Conjugated Polymers ◽  
Ground State ◽  
Charge Storage ◽  
Type I ◽  
Type Ii ◽  
State Type ◽  
Degenerate Ground State

Charge storage and charge transport in conducting polymers: solitons, polarons and bipolarons

1985 ◽  
Vol 314 (1528) ◽  
pp. 17-35 ◽  
Keyword(s):  
Conducting Polymers ◽  
Ground State ◽  
General Context ◽  
Charge Storage ◽  
Electron Hole ◽  
Nonlinear Excitations ◽  
Degenerate Ground State ◽  
Ground State Degeneracy ◽  
Series Of Experiments

The results of a series of experiments demonstrate that solitons are the important excitations in trans -(CH) x and that the properties of these nonlinear excitations can be directly studied during photoexcitation or after doping. The importance of these concepts in the more general context of conducting polymers is addressed. Although the twofold degenerate ground state of trans -(CH) x is quite special, the relevant concepts have been generalized to confined soliton pairs (bipolarons). Experimental results that demonstrate electron-hole symmetry and weak confinement in polythiophene make this polyheterocycle a nearly ideal example of a model system in which the ground-state degeneracy has been lifted. In the dilute doping regime, in situ absorption spectroscopy data (during electrochemical doping) strongly suggest charge storage via bipolarons with confinement parameter γ ≈ 0.1–0.2. These results on polythiophene demonstrate that a quantitative fundamental understanding is possible even for relatively complex systems.

scholarly journals Survey of OH Masers at 1665 MHz. II. Galactic Longitude 340o to the Galactic Centre

1983 ◽  
Vol 36 (3) ◽  
pp. 361 ◽  
Author(s):  
JL Caswell ◽  
RF Haynes
Keyword(s):  
Ground State ◽  
Galactic Plane ◽  
Line Emission ◽  
State Transitions ◽  
Galactic Centre ◽  
Emission Sources ◽  
Type I ◽  
Type Ii ◽  
Formation Type ◽  
Galactic Longitude

The galactic plane from longitude 340� through the galactic centre to longitude + 2� has been searched for OH on the 1665 MHz transition. Forty-nine OH maser emission sources were detected and these have now been studied on all four OH ground-state transitions. Most of the masers are associated with regions of star formation (type I) while three may be examples of late-type stars (type II OH/IR) with unusually strong main-line emission

scholarly journals Synchronization in Non-Mirror-Symmetrical Chirogenesis: Non-Helical π–Conjugated Polymers with Helical Polysilane Copolymers in Co-Colloids

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 594
Author(s):  
Michiya Fujiki ◽  
Shun Okazaki ◽  
Nor Azura Abdul Rahim ◽  
Takumi Yamada ◽  
Kotohiro Nomura
Keyword(s):  
Conjugated Polymers ◽  
Mirror Symmetry ◽  
Main Chain ◽  
Fundamental Question ◽  
Type I ◽  
Type Ii ◽  
Circularly Polarized ◽  
Chain Stiffness ◽  
Circularly Polarized Luminescence ◽  
Polarized Luminescence

A curious question is whether two types of chiroptical amplifications, called sergeants-and-soldiers (Ser-Sol) and majority-rule (Maj) effects, between non-charged helical copolymers and non-charged, non-helical homopolymers occur when copolymer encounter homopolymer in co-colloids. To address these topics, the present study chose (i) two helical polysilane copolymers (HCPSs) carrying (S)- or (R)-2-methylbutyl with isobutyl groups as chiral/achiral co-pendants (type I) and (S)- and (R)-2-methylbutyl groups as chiral/chiral co-pendants (type II) and (ii) two blue luminescent π-conjugated polymers, poly[(dioctylfluorene)-alt-(trans-vinylene)] (PFV8) and poly(dioctylfluorene) (PF8). Analyses of circular dichroism (CD) and circularly polarized luminescence (CPL) spectral datasets of the co-colloids indicated noticeable, chiroptical inversion in the Ser-Sol effect of PFV8/PF8 with type I HCPS. PF8 with type IIHCPS showed the anomalous Maj rule with chiroptical inversion though PFV8 with type IIHCPS was the normal Maj effect. The noticeable non-mirror-symmetric CD-and-CPL characteristics and marked differences in hydrodynamic sizes of these colloids were assumed to originate from non-mirror-symmetrical main-chain stiffness of HCPSs in dilute toluene solution. The present chirality/helicity transfer experiments alongside of previous/recent publications reported by other workers and us allowed to raise the fundamental question; is mirror symmetry on macroscopic levels in the ground and photoexcited states rigorously conserved?

Heat-Etching with a Bullivant Type II Simple Freeze-Cleave Device

1970 ◽  
Vol 28 ◽  
pp. 106-107 ◽  
Author(s):  
Ronald S. Weinstein ◽  
N. Scott McNutt
Keyword(s):  
New Zealand ◽  
General Hospital ◽  
Massachusetts General Hospital ◽  
Type I ◽  
Type Ii ◽  
Collaborative Effort ◽  
Temperature And Pressure ◽  
The University

The Type I simple cold block device was described by Bullivant and Ames in 1966 and represented the product of the first successful effort to simplify the equipment required to do sophisticated freeze-cleave techniques. Bullivant, Weinstein and Someda described the Type II device which is a modification of the Type I device and was developed as a collaborative effort at the Massachusetts General Hospital and the University of Auckland, New Zealand. The modifications reduced specimen contamination and provided controlled specimen warming for heat-etching of fracture faces. We have now tested the Mass. General Hospital version of the Type II device (called the “Type II-MGH device”) on a wide variety of biological specimens and have established temperature and pressure curves for routine heat-etching with the device.

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