4A16㧗ᙉᗘ㏆㉥እ࣮ࣞࢨ࣮࡟ࡼࡿ
C60 ࡢ࣮ࣔࢻ㑅ᢥⓗບ㉳࡜ゎ㞳ไᚚ࡟㛵ࡍࡿ⌮ㄽⓗ◊✲ᮾ໭኱㝔⌮ 1, ᮾ኱㝔⌮ 2, 㜰኱㝔⌮ 3, ዉⰋዪ኱⌮ ‫ۑ‬᪂ὠ┤ᖾ 1, ୰஭ඞ඾ 2, ụ⏣㞙ே 3, ᡞ⏣ᖿே 4, Ἑ㔝⿱ᙪ 1
 ගᙉᗘࡀ 1013 ࠿ࡽ 1015 W/cm2 ⛬ᗘࡢ㧗ᙉᗘ࣮ࣞࢨ࣮ࣃࣝࢫࢆ C60 ࡟↷ᑕࡍࡿ࡜ࠊከ౯ࡢぶ࢝ࢳ࢜ࣥࡸᵝࠎ࡞ゎ㞳✀ࡀ⌧ࢀࡿࠋࡇࡢࡼ࠺࡞ C60 ࡢゎ㞳࡜࢖࢜ࣥ໬ࡢ➇ྜ㐣⛬ࡣࠊࣃࣝࢫ㛗ࡸἼ㛗ࢆኚ࠼ࡿࡇ࡜࡟ࡼࡗ࡚ไᚚ࡛ࡁࡿࠋ౛࠼ࡤࠊἼ㛗 800 nm ࡢ࣮ࣞࢨ࣮ࣃࣝࢫࢆ⏝࠸ࡓᐇ㦂࡛ࡣࠊࣃࣝࢫ㛗ࡀ 5 ps ࡜㛗࠸ሙྜ࡟ࡣ C60!2n+ࡸ C2n+࡜࠸ࡗࡓゎ㞳⏕ᡂ≀ࡀᚓࡽࢀࡿࠋࡇࢀ࡟ᑐ
ࡋࣃࣝࢫ㛗ࡀ 25 fs ࡜▷࠸ሙྜ࡟ࡣࠊ5 ౯ࡲ࡛ࡢከ౯࢝ࢳ࢜ࣥࡀ⏕ᡂࡉࢀࠊゎ㞳⏕ᡂ≀ࡣ┦ᑐⓗ࡟ῶᑡࡍࡿ[1]ࠋ୍᪉ࠊἼ㛗 1800 nm ࡢ࣮ࣞࢨ࣮ࣃࣝࢫ࡛ࡣࠊ12 ౯ࡲ࡛ࡢ㉸ከ౯࢝ࢳ࢜ࣥࡀ⏕ᡂࡉࢀࠊゎ㞳ࡣ࡯࡜ࢇ࡝㉳ࡇࡽ࡞࠸[2]ࠋ᭱㏆࡛ࡣࠊἼ㛗 800 nm ࡢࣇ࢙࣒ࢺ⛊ࣃࣝࢫࢆἼᙧᩚᙧ
ࡍࡿࡇ࡜࡟ࡼࡗ࡚ࠊC50+ࡢࡼ࠺࡞≉ᐃࡢゎ㞳ࣇࣛࢢ࣓ࣥࢺࡢ཰⋡ࢆቑ኱ࡉࡏࡿᐇ㦂ࡀሗ࿌ࡉࢀ
࡚࠸ࡿࠋࡇࡢᐇ㦂࡛ࡣ㧗ᙉᗘ࣮ࣞࢨ࣮࡟ࡼࡗ࡚඲ᑐ⛠ࡢఙ⦰᣺ື࡛࠶ࡿ ag 1 ࣮ࣔࢻࡢ᣺ືࡀㄏ㉳ࡉࢀ࡚࠸ࡿࡇ࡜ࡀ♧၀ࡉࢀ࡚࠸ࡿࡀ[3]ࠊ୍⯡࡟ C60 ࡢࡼ࠺࡞኱ࡁ࡞ศᏊ࡛ࡣࠊὀධࡉࢀࡓ࢚ ࢿ ࣝ ࢠ ࣮ ࡣ ᣺ ື ࢚ ࢿ ࣝ ࢠ ࣮ ෌ ศ 㓄 㐣 ⛬ Intramolecular Vibrational Energy Redistribution 㸪IVR [4]࡟ࡼࡗ࡚」ᩘࡢ⤖ྜ࡬ᛴ㏿࡟෌ศ㓄ࡉࢀࠊ཯ᛂࡀධຊࡉࢀࡓ࢚ࢿࣝࢠ࣮࡟ࡢࡳ౫Ꮡࡍࡿ
࡜⪃࠼ࡽࢀ࡚࠸ࡿࠋࡇࡢࡓࡵࠊୖグࡢࡼ࠺࡞ไᚚࡀྍ⬟࡛࠶ࡿࡇ࡜ࡣ኱ኚ⯆࿡῝࠸ࠋᮏ◊✲࡛ࡣࠊࡇࡢࡼ࠺࡞ගບ㉳࡟ࡼࡿ C60 ࡢ཯ᛂไᚚࡢᶵᵓゎ᫂ࢆ┠ⓗ࡜ࡋࠊἼ㛗 1800 nm ࡢ㧗ᙉᗘ㏆㉥እ࣮ࣞࢨ࣮ࣃࣝࢫ࡟ࡼࡗ࡚ㄏ㉳ࡉࢀࡿ C60 ࡢ᣺ືࢲ࢖ࢼ࣑ࢡࢫࢆࠊ࣮ࣞࢨ࣮ሙ࡟ࡼࡗ࡚ṍࢇࡔ᩿⇕࣏ࢸࣥࢩࣕࣝࢆྲྀࡾ㎸ࢇࡔ➨୍ཎ⌮ືຊᏛィ⟬(᫬㛫౫Ꮡ᩿⇕≧ែἲ)࡟ࡼࡗ࡚[5]ࠊ᣺ື
ບ㉳ᚋࡢ㛗᫬㛫ࢲ࢖ࢼ࣑ࢡࢫࡣᐦᗘỗ㛵ᩘ⥭ᐦ⤖ྜ(Density-Functional Tight-Binding: DFTB)ἲ
ࢆ⏝࠸࡚ồࡵࠊC60 ࡢ᣺ື࡜ゎ㞳ࡢไᚚᶵᵓ࡟ࡘ࠸࡚ㄪ࡭ࡿࠋ ࡲࡎࠊ᫬㛫౫Ꮡ᩿⇕≧ែἲ࡟ࡼࡗ࡚ᚓࡽࢀࡓ⤖ᯝࢆࡲ࡜ࡵࡿࠋC60 ࡟ᑐࡋ࡚ࣃࣝࢫ㛗 Tp = 70 fs
࡜ Tp = 30 fs ࡢ༢ࣃࣝࢫ Ipeak = 71014 W/cm2 ࢆ↷ᑕࡋࡓሙྜ࡟ࡣࠊ࡝ࡕࡽࡢࣃࣝࢫ㛗࡟࠾࠸࡚ࡶ೫㛗࡜ᡥᖹࡢᵓ㐀ኚ໬ࢆ⧞ࡾ㏉ࡍ hg 1 ࣮ࣔࢻ(᣺ື࿘ᮇ Tvib = 125 fs)ࡀ᭱ࡶᙉࡃㄏ㉳ࡉࢀ࡚࠸ࡓ ᅗ 1 ࠋTp = 70 fs ࡢሙྜ࡟ࡣࠊ඲య࡛⋓ᚓࡋࡓ 30 eV ࡢ࢚ࢿࣝࢠ࣮ࡢ࠺ࡕࠊhg 1 ࡟ 14 eVࠊ
ag 1 ࡟ 4 eV ࡢ࢚ࢿࣝࢠ࣮ࡀ
ὀධࡉࢀ࡚࠸ࡓࠋ୍᪉ Tp = 30fs ࡢሙྜ࡟ࡣࠊ඲య࡛ 20 eV⛬ࡢ࢚ࢿࣝࢠ࣮ࢆ⋓ᚓࡋࠊhg 1 ࡟ 8 eVࠊag 1 ࡟ 5 eV ࡢ࢚ࢿࣝࢠ࣮ࡀὀධࡉࢀ࡚࠾ࡾࠊ
ag 1 ࣮ࣔࢻ(Tvib = 67 fs)ࡀ Tp= 70 fs ࡢሙྜ࡜ẚ࡭࡚┦ᑐⓗ࡟ㄏ㉳ࡉࢀ࡚࠸ࡓࠋࡇࢀ࡟ࡼ
ࡾࠊࣃࣝࢫ㛗ࡢ 2 ಸࡢ᣺ື࿘

ᅗ1࢞࢘ࢫᆺࡢ༢ࣃࣝࢫ Ἴ㛗 ! =1800 nm, ගࣆ࣮ࢡᙉᮇࢆᣢࡘ≉ᐃࡢ࣐ࣛࣥάᛶࣔ

ᗘ Ipeak =7 " 1014 W/cm2, Tp = 30 fs ࡜┦஫స⏝ࡍࡿ C60 ࡢ➨୍࣮ࢻࡀᙉࡃບ㉳ࡉࢀࡿࡇ࡜ࡀ

ཎ⌮ືຊᏛࢩ࣑࣮ࣗࣞࢩࣙࣥࠋhg 1 ࣮ࣔࢻࡢ᣺ືࡀᙉࡃບ㉳᫂ࡽ࠿࡜࡞ࡗࡓࠋ

ࡉࢀࡿࠋ೫ග᪉ྥࡣ⣬㠃ࡢୖୗ᪉ྥࠊTime = 0 ࡣࣃࣝࢫࡢࣆ࣮ࢡ᫬้࡛࠶ࡿࠋ

ḟ࡟ࠊ2 ࡘࡢࣃࣝࢫ Ȣ= 1800 nm, Ipeak= 71014 W/cm2, Tp= 30 fs ࢆ᫬㛫ᕪȫࢆኚ࠼࡚ C60 ࡟↷ᑕࡋࡓሙྜࡢࢲ࢖ࢼ࣑ࢡࢫィ⟬ࢆ⾜ࡗࡓࠋࡇࡢሙྜ࡟ࡣࠊᅗ 2 ࡟♧ࡍࡼ࠺࡟ࠊ2 ࡘ┠ࡢࣃࣝࢫࢆ↷ᑕࡍࡿࢱ࢖࣑ࣥࢢ࡟ࡼࡗ࡚ㄏ㉳ࡉࢀࡿ᣺ື࣮ࣔࢻ࡟኱ࡁ࡞㐪࠸ࡀぢࡽࢀࡓࠋȫ= 134 fs ࡢሙྜ࡛ࡣࠊ༢ࣃࣝࢫࡢሙྜ࡜ẚ࡭࡚ hg 1 ࣮ࣔࢻࡀࡼࡾᙉࡃບ㉳ࡉࢀࡓࠋࡇࢀࡣࠊȫࡀ hg 1 ࡢ᣺ື࿘ᮇ 125 fs ࡟㏆࠸ࡓࡵ࡛࠶ࡿࠋࡇࡢ࡜ࡁ C60 ඲య࡛ࡣ 60 eV ࡶࡢ࢚ࢿࣝࢠ࣮ࢆ⋓ᚓࡋ࡚࠸ࡓࡀࠊࣆࢥ⛊㡿ᇦ࡛ࡣㄪ࿴᣺ືࡀᣢ⥆ࡋࠊゎ㞳ࡣࡋ࡞࠿ࡗࡓࠋȫ= 201 fs ࡢሙྜࡣࠊ⋓ᚓࡋࡓ⥲࢚ࢿࣝࢠ࣮ࡣ༢ࣃࣝࢫࡢሙྜ࡜࡯࡜ࢇ࡝ኚࢃࡽ࡞࠿ࡗࡓࡀࠊ୺せ࡞᣺ືࡀ ag 1 ࣮ࣔࢻ࡟ࢫ࢖ࢵࢳࡉࢀ࡚࠾ࡾࠊࣃࣝࢫิࢆ⏝࠸ࡿࡇ࡜࡛ࠊ᣺ືບ㉳ࡢไᚚࡀྍ⬟࡛࠶ࡿࡇ࡜ࡀ♧ࡉࢀࡓࠋhg(1)䝰䞊䝗䛻ᑐᛂ

Intensity

300200ᅗ2ag(1)䝰䞊䝗䛻ᑐᛂࣃ ࣝ ࢫ !#= 1800 nm, Ipeak = 7 " 1014

W/cm2, Tp = 30 fs ↷ᑕᚋࡢ C60 ࡢ࣏ࢸࣥࢩ࢚ࣕࣝ
ࢿࣝࢠ࣮ࡢ᫬㛫ኚ໬࡟ྵࡲࢀࡿ᣺ືᩘᡂศࠋࣃ
ࣝࢫ㛫㝸#$࡟ࡼࡗ࡚ບ㉳ࡉࢀࡿ᣺ື࣮ࣔࢻࡀኚ

100ࢃࡿࡇ࡜ࡀ☜ㄆ࡛ࡁࡓࠋᐇ⥺(㉥)㸸ȫ= 134 fs, Ⅼ00⥺(㟷)㸸ȫ= 201 fs, ◚⥺(⥳)㸸༢ࣃࣝࢫࠋ

500 1000 1500 2000%&Frequency / cm⥆࠸࡚ࠊ࣮ࣞࢨ࣮ࣃࣝࢫ࡛ ag(1)ࡸ hg(1)ࡢ᣺ື࣮ࣔࢻࡀບ㉳ࡉࢀࡓ࡜௬ᐃࡋࠊゎ㞳ࡲ࡛ࡢ᫬㛫࠾ࡼࡧゎ㞳ࡢ≉ᚩ࡟ࡘ࠸࡚ࠊὀධࡉࢀࡓ࢚ࢿࣝࢠ࣮࡜ࡢ㛵ಀࢆㄪ࡭ࡓࠋag(1)࣮ࣔࢻࢆ
ບ㉳ࡋࡓሙྜ࡟ࡣࠊゎ㞳㏿ᗘࡀ⤫ィ⌮ㄽ࡟ᚑ࠺ഴྥࢆぢࡏࡓࡢ࡟ᑐࡋࠊhg(1)࣮ࣔࢻࢆບ㉳ࡋࡓሙྜ࡟ࡣࠊࢣ࣮ࢪᵓ㐀ࢆಖᣢࡋ࡚ࡢゎ㞳ࡸࠊ᣺ືࡢ 1 ࿘ᮇෆࡢゎ㞳࡞࡝ࠊࡑࡢ≉ᚩࡈ࡜࡟ゎ㞳㏿ᗘࡀẁ㝵ⓗ࡟ኚ໬ࡍࡿ࡜࠸࠺⤖ᯝࡀᚓࡽࢀࠊゎ㞳㏿ᗘࡢึᮇບ㉳᣺ື౫Ꮡᛶࡀ
ぢฟࡉࢀࡓࠋࡲࡓࠊゎ㞳ࡢ㐣⛬࡟࠾࠸࡚ Stone-Wales ㌿఩[6]࡟ࡼࡿ C60 ࡢࢿࢵࢺ࣮࣡ࢡᵓ㐀ࡢ ኚ ໬ ࡀ ☜ ㄆ ࡉ ࢀ ࡓ ( ᅗ 3) ࠋ 」 ᩘ ᅇ ࡢ
Stone-Wales ㌿఩࡟ࡼࡗ࡚」㞧࡟ࢿࢵࢺ࣮࣡ࢡᵓ㐀ࡀኚ໬ࡍࡿ࡯࡝ࠊゎ㞳㏿ᗘࡀ㐜ࡃ࡞ࡿഴྥࡀぢࡽࢀࠊゎ㞳㏿ᗘ࡟ࢿࢵࢺ
࣮࣡ࢡᵓ㐀ࡢኚ໬ࡀᙳ㡪ࡋ࡚࠸ࡿࡇ࡜ࡀ᫂ࡽ࠿࡜࡞ࡗࡓࠋ
[1] I. V. Hertel et al. Adv. At. Mol. Opt. Phys. 50,
219 (2005). [2] V. R. Bhardwaj et al. Phys. Rev.
Lett., 91, 203004 (2003). [3] T. Laarmann et al.
Phys. Rev. Lett., 98,058302 (2007).
[4] J. Jortner and R. D. Levine, in Mode
Selective Chemistry, ed. J. Jortner, R. D. Levineand B.Pullman (Kluwer, Dordrecht, 1991) p. 535.
[5] K. Nakai et al. Chem. Phys. 338, 127-134(2007). [6] A. J. Stone and D. J. Wales, Chem.
Phys. Lett. 128, 501-503 (1986).

ᅗ3ag(1)࣮ࣔࢻࡢ᣺ື࡟ 63 eV ࢆὀධࡋࡓࢩ࣑࣮ࣗࣞࢩ࡛ࣙࣥᚓࡽࢀࡓ Stone-Wales㌿఩࠾ࡼࡧࡑࢀ࡟క࠺ゎ㞳ࡢᵝᏊࠋ⥳ࡢⅣ⣲㛫⤖ྜࡀᅇ㌿ࡋࠊᕥୗᅗࡢ㟷Ⰽ⥺࡛♧ࡋࡓࡼ࠺࡞2 ࡘࡢ 5 ဨ⎔ࡀ┤᥋㞄᥋ࡋࡓᵓ㐀ࡀ⏕ࡌࡿࠋ