M.I.T. political-military gaming experience

"February 1965.""1552"--handwritten on cove

First-principles high pressure structure searching, longitudinal-transverse mode coupling and absence of simple cubic phase in sulfur

Abstract: We use first-principles density functional theory to conduct an extensive structure search using the AIRSS package for elemental sulfur in the range 50–550 GPa. We then obtain the low-temperature phase diagram of sulfur in the same pressure range, including vibrational effects through the harmonic approximation. We do not find any structures lower in energy than those already reported in experiment, although the phase diagram below 100 GPa is found to be crowded with structures separated by only a few meV. We report the transition sequence I 4 1 / acd → P 1 ¯ → ICM → C 2 / m → R 3 ¯ m → I m 3 ¯ m and obtain accurate pressures for each transition, although we find the second-order C 2 / m → R 3 ¯ m transition particularly difficult to define. Contrary to previous first-principles works (Pavel et al; Rudin and Liu 1999 Phys. Rev. Lett. 83 3049–52), we do not reproduce a trigonal → simple cubic transition at either the static lattice or harmonic level. We also undertake a detailed analysis of the incommensurately modulated (ICM) phase of sulfur phase using a commensurate approximant found in the structure search. We find that the modulation amplitude is zero above 96 GPa; some 40 GPa below the experimentally reported transition to the unmodulated phase. We find that the body-centred atoms in the relaxed ICM approximant are, in addition to the dominant transverse modulation (which is a frozen-in optical phonon mode), slightly displaced longitudinally in the b-direction. We subsequently discover that this (small) longitudinal modulation is coupled to the transverse mode, and hence report previously unnoticed weak-mode coupling between transverse and longitudinal optical phonons in the ICM phase

The Ursinus Weekly, May 9, 1974

Saturday Parent\u27s Day • Songfest big hit • Gordon unravels mystery of Vineland map • Twelve chapter scholars picked • Chalk Circle opens tonight • Editorial: Crisis key: Constitution • Final examination schedule • To the editor: Friendshiphttps://digitalcommons.ursinus.edu/weekly/1016/thumbnail.jp

Blueshift and intramolecular tunneling of NH[sub 3] umbrella mode in [sup 4]He[sub n] clusters

International audienceWe present diffusion Monte Carlo calculations of the ground and first excited vibrational states of NH(3) (4)He(n) for n< or =40. We use the potential energy surface developed by one of us [M. P. Hodges and R. J. Wheatley, J. Chem. Phys. 114, 8836 (2001)], which includes the umbrella mode coordinate of NH(3). Using quantum Monte Carlo calculations of excited states, we show that this potential is able to reproduce qualitatively the experimentally observed effects of the helium environment, namely, a blueshift of the umbrella mode frequency and a reduction of the tunneling splittings in ground and first excited vibrational states of the molecule. These basic features are found to result regardless of whether dynamical approximations or exact calculations are employed

The Ursinus Weekly, February 27, 1975

Women\u27s open dorms suspended for Friday P.M. • Forum: Savitch reports • Festival of Arts includes music, crafts and dance • Union creates Hell\u27s Half Acre • 1975 interview schedule • Bloodmobile will visit U.C. campus • Football team donates gift to Varsity Club • Focus: Dean Ruth R. Harris; George P. Kinek • Editorial: Time for all or time for none • Can the Flyers repeat? • Overtime jinx • Yes we can in 1975 • Badminton: Good • Hoopla • U.C. grapplers end seasonhttps://digitalcommons.ursinus.edu/weekly/1030/thumbnail.jp

The Ursinus Weekly, September 26, 1974

Fall Forum season opens • Editorial: Dear freshmen • A Guide to better living in Collegeville, Pa. 19426 • Bears 1974 football preview • Harriers upset by Delaware Valleyhttps://digitalcommons.ursinus.edu/weekly/1019/thumbnail.jp

The Ursinus Weekly, February 13, 1975

Forum will host Jessica Savitch • Lorelei: Midnite at the oasis • Forum review: Morgenthau delivers informative address on complex topic • Classics performed by Temple orchestra • U.C. Chaplain plans Lenten experiences • Purloined pitchers • Music groups active • Phlash! • Interaction between Ursinus past and present • We place ourselves at your disposal • 1975 interview schedule • The old gold remains • New addition to education faculty • The travails of Knorft • Millions for Ursinus • Bears beat Hopkins; Lose to Muhlenberg • Hockey team returns with memories of Great Britain • Spring flicks at Union • Girls\u27 basketball • Distinguished wrestler named coach • Swimmers splash alonghttps://digitalcommons.ursinus.edu/weekly/1029/thumbnail.jp

The Ursinus Weekly, May 30, 1974

Cindy Cole named valedictorian • Four to receive honorary degrees at commencement • Summer use planned for college facilities • New member added to Phys. Ed. faculty • New Assistant Dean of Women is appointed • New instructor of philosophy named • Two professors receive quarter century awards • Dr. Visser writes history text manual • Dr. Cope elected to Phi Beta Kappa office • Editorial: Money talks?; Farewell • Alumni Corner: The extra-curricular teacher • To the editor: The cracked shell • Goal is near • Change in Lancaster • Focus: The head on that guy! • Deferred degrees received • Faculty focus: Ursinus past and presenthttps://digitalcommons.ursinus.edu/weekly/1018/thumbnail.jp