How well do Car-Parrinello simulations reproduce the Born-Oppenheimer surface ? Theory and Examples

We derive an analytic expression for the average difference between the forces on the ions in a Car-Parrinello simulation and the forces obtained at the same ionic positions when the electrons are at their ground state. We show that for common values of the fictitious electron mass, a systematic bias may affect the Car-Parrinello forces in systems where the electron-ion coupling is large. We show that in the limit where the electronic orbitals are rigidly dragged by the ions the difference between the two dynamics amounts to a rescaling of the ionic masses, thereby leaving the thermodynamics intact. We study the examples of crystalline magnesium oxide and crystalline and molten silicon. We find that for crystalline silicon the errors are very small. For crystalline MgO the errors are very large but the dynamics can be quite well corrected within the rigid-ion model. We conclude that it is important to control the effect of the electron mass parameter on the quantities extracted from Car-Parrinello simulations.Comment: Submitted to the Journal of Chemical Physic

Проектна діяльність бібліотек та інформаційних установ

Робоча навчальна програма «Проектна діяльність бібліотек та інформаційних установ» за напрямом підготовки 6.020102 «Книгознавство, бібліотекознавство і бібліографія», галузі знань 0201 «Культура», освітній рівень: перший (бакалаврський). - 2017 р

A La bein Aimee

Illustration of lighthouse on shore with boats in oceanhttps://scholarsjunction.msstate.edu/cht-sheet-music/11920/thumbnail.jp

Multicultural TeKu : the international learning environment at Savonia

The objective of this paper is to investigate the situation of the foreign students at Savonia University of Applied Sciences, Engineering Kuopio. Students coming from different cultures face different kind of obstacles concerned to learning As well in their normal ‘every day’ life caused by e.g. social, economical or language reasons. What are these challenges they have to deal with? Key questions are how comfortable the foreign students feel in their study environment, how well are they integrated into school’s network‐ and social environment. Besides the scientific approach to the subject of intercultural learning environment there will be also a discussion from both the students and teachers side of general study related problems. The kernel of the empirical part is a questionnaire for the foreign students supported by interviews and free discussions withstudents and teachers. As a summary I try to find suggestion to address these cultural differences and the problems of the students when organizing te curriculum and implement the teaching

Valse mignonne, op. 16, no. 2 ... [music] /

Mode of access: Internet

Het natuurlijk kapitaal van de Lutkemeerpolder

Due to high demands for housing and economic activities the main green infrastructure (groen scheggen) of Amsterdam is under pressure. The Lutkemeerpolder, part of this green infrastructure (Scheg van West) will be transformed into a business park; a choice that was made twenty years ago but the development still meets resistance from local residents. Foundation Behoud Lutkemeerpolder asked the Science Shop of Wageningen University and Research to determine the value of the ecosystem services of the polder. The research, based on The Economics of Ecosystems and Biodiversity (TEEB, 2010) highlight for important ecosystem services: 1) food production, 2) air purification, 3) recreation, and 4) the effect of greenery on housing prices. The total monetary value of the ecosystem services is estimated at 1.5 to 8.6 million euros per year. These values were not included in the decision making twenty years ago. It is recommended to reconsider the decision made at the time and calculate the consequences of various development scenarios. The need to take care of the remaining nature has only grown over the past twenty years. Ecosystem services can no longer be taken for granted

Walzer-Märchen; arr.

31 p. of music ; 30 cm

Russian folk-song / transcribed by Eduard Schütt

7 p. of music ; 31 c

Episoden (Fünf Stimmungsbilder): Trio für Pianoforte, Violine und Violoncelle. Op. 72.

score (1 v.) and parts. 34 cm

Andante cantabile, pianos (2), op. 79, no. 1

2 scores (10 p. each) ; 31 c