Single molecule's electric charges seen in first image

  BBC

The team's first-ever charge distribution measurements (top) matched neatly with theory

 

Researchers have shown off the first images of the "charge distribution" in a single molecule, showing an intricate dance of electrons at tiny scales.

Charges on single atoms have been measured before, but capturing the dance within a complex molecule is significantly more difficult.
The pioneering measurement could shed light on a range of "charge-transfer" processes that are common in nature.
Details are reported in the journal Nature Nanotechnology.
The work comes from a group at IBM Research Zurich that specialises in examining the world at the infinitesimal scale of atoms and molecules.
The same team is responsible for the measurement of charge on single atoms, as well as the first image of a single molecule - in a sense the new work is a combination of those two views.
However, it makes use of a different technique, called Kelvin probe microscopy. It is a variant of the atomic force microscopy that allowed the first molecular image in 2009.
It requires a tiny bar just billionths of a metre across and with a sharp tip that ends in a single small molecule. This bar, or cantilever, is held at a small voltage while it is scanned across the surface of a much larger, X-shaped molecule, naphthalocyanine.
As the charged tip encounters charges within the naphthalocyanine, the cantilever begins wagging in a way that shows up precisely where the electrons are.
The trick of naphthalocyanine, though, is that by applying a voltage to the molecule directly, two hydrogen atoms at its centre swap places, and the electrons reshuffle to opposite arms of the "X".
With the team's technique, they were able to observe this change in charge distribution.
In combination with more established techniques, the approach will shed light on the nanoscale world that is promising not only for fundamental science, but also for future applications in which electric behaviour at such scales will be exploited.
"It will now be possible to investigate at the single-molecule level how charge is redistributed when individual chemical bonds are formed between atoms and molecules on surfaces," said lead author of the research Fabian Mohn.
"This is essential as we seek to build atomic and molecular scale devices."

Sri Lanka university teachers set deadline for the government to grant their demands

Sri Lanka university teachers set deadline for the government to grant their demandsSun, Feb 26, 2012, 12:51 pm SL Time, ColomboPage News Desk, Sri Lanka.
Feb 26, Colombo: University teachers in Sri Lanka have given a deadline to the government to grant their demands and threatened to initiate stern trade union action if the demands were not granted by then.
The executive committee of the Federation of University Teachers' Associations (FUTA) that met on February 24 has decided allow until March 15 to grant their demands.
The FUTA has informed the decision to the Ministry of Higher Education in writing, says Dr. Nirmal Ranjith Devasiri, the Chairman of the Federation.
"The Ministry has been given till March 15th to address the lecturers' issues, especially the promised salary hike," he has told the media.
The FUTA says that the government has agreed to implement the salary revision granted to them in four stages.
However, the second stage that was to be implemented from January this year has not realized yet, the union says.
The government granted this salary revision to the university teachers following a lengthy trade union action last year.
Dr. Devasiri says that the university teachers are also demanding an increase for the evaluation of answer scripts of the internal examinations and also an increase of the allowances for the visiting lecturers.

=========== Courtesy : Colombopage.com

Non-academic staff agitation emboldens varsity dons

February 26, 2012, 10:13 pm , The Island.

by Dasun Edirisinghe

In the wake of university non academic staff successfully staging a 48 – hour token strike on Feb. 23 and 24, university teachers again threatened an all out strike from March 15 if the government failed to resolve their grievances shortly.

President of the Federation of University Teachers Associations Dr. Nirmal Ranjith Devasiri said that the President Mahinda Rajapaksa himself had broken the promise to grant their salary increments through the budget 2012.

"We entered the warpath again with the main demand to abolish the proposed private university bill," he said adding that the government had yet to consult them on the proposed bill.

He said finally they staged a token strike on Jan. 18, but the higher education ministry still turned a blind eye to the issue.

Dr. Devasiri, however said that at a meeting held after the token strike Higher Education Minister S. B. Dissanayake promised to consult them on the private university bill and discuss the draft bill.

"Unfortunately Minister Dissanayake too broke the promise," he said.

The senior academic said they resorted to trade union action during first half of the last year by vacating from all volunteer posts they held in protest of the government’s delay to increase their salaries.

The university teachers temporarily suspended their trade union action in June last year on the promise of President Rajapaksa, but with the threat to revive at any time, Dr. Devasiri said.